diff --git a/qhtcp-workflow/apps/r/calculate_interaction_zscores.R b/qhtcp-workflow/apps/r/calculate_interaction_zscores.R
index 8dd976c3..1d5b857b 100644
--- a/qhtcp-workflow/apps/r/calculate_interaction_zscores.R
+++ b/qhtcp-workflow/apps/r/calculate_interaction_zscores.R
@@ -116,7 +116,7 @@ scale_colour_publication <- function(...) {
 # Load the initial dataframe from the easy_results_file
 load_and_process_data <- function(easy_results_file, sd = 3) {
   df <- read.delim(easy_results_file, skip = 2, as.is = TRUE, row.names = 1, strip.white = TRUE)
-  
+
   df <- df %>%
     filter(!(.[[1]] %in% c("", "Scan"))) %>%
     filter(!is.na(ORF) & ORF != "" & !Gene %in% c("BLANK", "Blank", "blank") & Drug != "BMH21") %>%
@@ -130,13 +130,14 @@ load_and_process_data <- function(easy_results_file, sd = 3) {
       DB = if_else(delta_bg >= delta_bg_tolerance, 1, 0),
       SM = 0,
       OrfRep = if_else(ORF == "YDL227C", "YDL227C", OrfRep), # should these be hardcoded?
-      conc_num = as.numeric(gsub("[^0-9\\.]", "", Conc)),
-      conc_num_factor = as.factor(conc_num)
-      # conc_num_factor = factor(conc_num, levels = sort(unique(conc_num)))
+      conc_num = as.numeric(gsub("[^0-9\\.]", "", Conc))
+    ) %>%
+    mutate(
+      conc_num_factor = as.factor(match(conc_num, sort(unique(conc_num))) - 1)
     )
-  
-  return(df)
-}
+    
+    return(df)
+  }
 
 # Update Gene names using the SGD gene list
 update_gene_names <- function(df, sgd_gene_list) {
@@ -160,15 +161,6 @@ update_gene_names <- function(df, sgd_gene_list) {
 
 calculate_summary_stats <- function(df, variables, group_vars) {
 
-
-  summary_stats <- df %>%
-    group_by(across(all_of(group_vars))) %>%
-    summarise(
-      N = n(),
-      sd_check = sd(L, na.rm = TRUE),  # Test sd on a specific variable, e.g., L
-      se_check = sd(L, na.rm = TRUE) / sqrt(N)  # Test se on a specific variable, e.g., L
-    )
-
   summary_stats <- df %>%
     group_by(across(all_of(group_vars))) %>%
     summarise(
@@ -184,9 +176,6 @@ calculate_summary_stats <- function(df, variables, group_vars) {
       .groups = "drop"
     )
 
-  # sd = ~sd(., na.rm = TRUE)
-  # se = ~sd(., na.rm = TRUE) / sqrt(sum(!is.na(.)) - 1)
-
   # Create a cleaned version of df that doesn't overlap with summary_stats
   cols_to_keep <- setdiff(names(df), names(summary_stats)[-which(names(summary_stats) %in% group_vars)])
   df_cleaned <- df %>%
@@ -219,11 +208,11 @@ calculate_interaction_scores <- function(df, max_conc, variables, group_vars) {
 
   stats <- calculate_summary_stats(df,
     variables = variables,
-    group_vars = c("OrfRep", "Gene", "num", "conc_num_factor"
-    ))$summary_stats
+    group_vars = c("OrfRep", "Gene", "num", "conc_num", "conc_num_factor")
+    )$summary_stats
 
   stats <- df %>%
-    group_by(OrfRep, Gene, num) %>%
+    group_by(across(all_of(group_vars))) %>%
     mutate(
       WT_L = mean_L,
       WT_K = mean_K,
@@ -277,13 +266,13 @@ calculate_interaction_scores <- function(df, max_conc, variables, group_vars) {
     )
 
   # Calculate linear models
-  lm_L <- lm(Delta_L ~ conc_num_factor, data = stats)
-  lm_K <- lm(Delta_K ~ conc_num_factor, data = stats)
-  lm_r <- lm(Delta_r ~ conc_num_factor, data = stats)
-  lm_AUC <- lm(Delta_AUC ~ conc_num_factor, data = stats)
+  lm_L <- lm(Delta_L ~ conc_num, data = stats)
+  lm_K <- lm(Delta_K ~ conc_num, data = stats)
+  lm_r <- lm(Delta_r ~ conc_num, data = stats)
+  lm_AUC <- lm(Delta_AUC ~ conc_num, data = stats)
 
   interactions <- stats %>%
-    group_by(OrfRep, Gene, num) %>%
+    group_by(across(all_of(group_vars))) %>%
     summarise(
       OrfRep = first(OrfRep),
       Gene = first(Gene),
@@ -357,10 +346,10 @@ calculate_interaction_scores <- function(df, max_conc, variables, group_vars) {
       "NG", "SM", "DB")
     
   calculations_joined <- df %>% select(-any_of(setdiff(names(calculations), c("OrfRep", "Gene", "num", "conc_num", "conc_num_factor"))))
-  calculations_joined <- left_join(calculations_joined, calculations, by = c("OrfRep", "Gene", "num", "conc_num_factor"))
+  calculations_joined <- left_join(calculations_joined, calculations, by = c("OrfRep", "Gene", "num", "conc_num", "conc_num_factor"))
 
   interactions_joined <- df %>% select(-any_of(setdiff(names(interactions), c("OrfRep", "Gene", "num", "conc_num", "conc_num_factor"))))
-  interactions_joined <- left_join(interactions_joined, interactions, by = c("OrfRep", "Gene", "num", "conc_num_factor"))
+  interactions_joined <- left_join(interactions_joined, interactions, by = c("OrfRep", "Gene", "num", "conc_num", "conc_num_factor"))
 
   return(list(calculations = calculations, interactions = interactions, interactions_joined = interactions_joined,
     calculations_joined = calculations_joined))
@@ -1059,7 +1048,7 @@ main <- function() {
     ss <- calculate_summary_stats(
       df = df,
       variables = summary_vars,
-      group_vars = c("OrfRep", "conc_num_factor"))
+      group_vars = c("conc_num", "conc_num_factor"))
     df_stats <- ss$df_with_stats
     message("Filtering non-finite data")
     df_filtered_stats <- filter_data(df_stats, c("L"), nf = TRUE)
@@ -1068,7 +1057,7 @@ main <- function() {
     ss <- calculate_summary_stats(
       df = df_na,
       variables = summary_vars,
-      group_vars = c("OrfRep", "conc_num_factor"))
+      group_vars = c("conc_num", "conc_num_factor"))
     df_na_ss <- ss$summary_stats
     df_na_stats <- ss$df_with_stats
     write.csv(df_na_ss, file = file.path(out_dir, "summary_stats_all_strains.csv"), row.names = FALSE)
@@ -1078,7 +1067,7 @@ main <- function() {
     ss <- calculate_summary_stats(
       df = df_no_zeros,
       variables = summary_vars,
-      group_vars = c("OrfRep", "conc_num_factor"))
+      group_vars = c("conc_num", "conc_num_factor"))
     df_no_zeros_stats <- ss$df_with_stats
     df_no_zeros_filtered_stats <- filter_data(df_no_zeros_stats, c("L"), nf = TRUE)
 
@@ -1090,14 +1079,14 @@ main <- function() {
 
     message("Calculating summary statistics for L within 2SD of K")
     # TODO We're omitting the original z_max calculation, not sure if needed?
-    ss <- calculate_summary_stats(df_na_within_2sd_k, "L", group_vars = c("conc_num_factor"))
+    ss <- calculate_summary_stats(df_na_within_2sd_k, "L", group_vars = c("conc_num", "conc_num_factor"))
     # df_na_l_within_2sd_k_stats <- ss$df_with_stats
     write.csv(ss$summary_stats,
       file = file.path(out_dir_qc, "max_observed_L_vals_for_spots_within_2sd_K.csv"),
       row.names = FALSE)
     
     message("Calculating summary statistics for L outside 2SD of K")
-    ss <- calculate_summary_stats(df_na_outside_2sd_k, "L", group_vars = c("conc_num_factor"))
+    ss <- calculate_summary_stats(df_na_outside_2sd_k, "L", group_vars = c("conc_num", "conc_num_factor"))
     df_na_l_outside_2sd_k_stats <- ss$df_with_stats
     write.csv(ss$summary_stats,
       file = file.path(out_dir, "max_observed_L_vals_for_spots_outside_2sd_K.csv"),
@@ -1272,7 +1261,7 @@ main <- function() {
       # Set the missing values to the highest theoretical value at each drug conc for L
       # Leave other values as 0 for the max/min
       reference_strain <- df_reference %>%
-        group_by(conc_num_factor) %>%
+        group_by(conc_num, conc_num_factor) %>%
         mutate(
           max_l_theoretical = max(max_L, na.rm = TRUE),
           L = ifelse(L == 0 & !is.na(L) & conc_num > 0, max_l_theoretical, L),
@@ -1282,7 +1271,7 @@ main <- function() {
 
       # Ditto for deletion strains
       deletion_strains <- df_deletion %>%
-        group_by(conc_num_factor) %>%
+        group_by(conc_num, conc_num_factor) %>%
         mutate(
           max_l_theoretical = max(max_L, na.rm = TRUE),
           L = ifelse(L == 0 & !is.na(L) & conc_num > 0, max_l_theoretical, L),