AWK - using substr integer as part of if condition

I'm attempting to use awk one liner to print lines of a file in which the substring is less than a defined variable. Also the line must start with the letter E. The E condition is working, but not the result for the simple if 'less than' I'm looking for. What am I doing wrong here?? It is incorporated into a larger bash script. Thanks in advance.

#!/bin/bash
minimum_dpt=50

awk -v depth="$minimum_dpt" '{if (/^E/ && int(substr($0,65,6)<depth)) print "Shot: ",substr($0,21,5)," has depth below minimum. Value: ",substr($0,65,6)'}