+ return 0 unless $cust_main; #sanity check
+ return 0 unless $cust_main->referral_custnum;
+
+ my $referring_cust_main = $cust_main->referral_custnum_cust_main;
+ return 0 unless $referring_cust_main; #sanity check;
+
+ #referring customer must sign up before referred customer
+ return 0 unless $cust_main->signupdate > $referring_cust_main->signupdate;