diff --git a/R/coding.R b/R/coding.R
index 443fb8a..52ee41a 100644
--- a/R/coding.R
+++ b/R/coding.R
@@ -627,7 +627,7 @@ coding <- function(chr,gene_name,genofile,obj_nullmodel,genes,
 						results_m[length(results_m)] <- 1
 					}
 
-					apc_num <- (length(results_m)-10)/6
+					apc_num <- (length(results_m)-10)/2
 					p_seq <- c(1:apc_num,1:apc_num+(apc_num+1),(length(results_m)-6):(length(results_m)-5))
 
 					## calculate STAAR-B
diff --git a/R/coding_incl_ptv.R b/R/coding_incl_ptv.R
index d7ff50c..c03cbc5 100644
--- a/R/coding_incl_ptv.R
+++ b/R/coding_incl_ptv.R
@@ -844,7 +844,7 @@ coding_incl_ptv <- function(chr,gene_name,genofile,obj_nullmodel,genes,
 						results_m[length(results_m)] <- 1
 					}
 
-					apc_num <- (length(results_m)-10)/6
+					apc_num <- (length(results_m)-10)/2
 					p_seq <- c(1:apc_num,1:apc_num+(apc_num+1),(length(results_m)-6):(length(results_m)-5))
 
 					## calculate STAAR-B
diff --git a/R/missense.R b/R/missense.R
index 6596f0b..5018438 100644
--- a/R/missense.R
+++ b/R/missense.R
@@ -356,7 +356,7 @@ missense <- function(chr,gene_name,genofile,obj_nullmodel,genes,
 						results_m[length(results_m)] <- 1
 					}
 
-					apc_num <- (length(results_m)-10)/6
+					apc_num <- (length(results_m)-10)/2
 					p_seq <- c(1:apc_num,1:apc_num+(apc_num+1),(length(results_m)-6):(length(results_m)-5))
 
 					## calculate STAAR-B
diff --git a/R/missense_cond_spa.R b/R/missense_cond_spa.R
index 965db16..89cbc8f 100644
--- a/R/missense_cond_spa.R
+++ b/R/missense_cond_spa.R
@@ -328,7 +328,7 @@ missense_cond_spa <- function(chr,gene_name,genofile,obj_nullmodel,genes,known_l
 					results_m[length(results_m)] <- 1
 				}
 
-				apc_num <- (length(results_m)-10)/6
+				apc_num <- (length(results_m)-10)/2
 				p_seq <- c(1:apc_num,1:apc_num+(apc_num+1),(length(results_m)-6):(length(results_m)-5))
 
 				## calculate STAAR-B