I have modified the original invoice footer with 2 format options by parameter field on Bill Type for user to select the format when printing.

Example 
Footer A for Standing Billing
Footer B for Tenant Billing

Below is the formula from the existing sage invoice in both footer that will show the footer at last page when printing

//NOT {@DoPrintContMsg}
WhilePrintingRecords;
numberVar grp2footer;
if grp2footer = 0 then TRUE else FALSE;

So I added below formula to suppress in footer A

if {?Bill Type} = "Tenant Billing" THEN true ELSE false;

and in Footer B:

if {?Bill Type} = "Tenant Billing" THEN false ELSE true;

But it turn out both overlap when printing either one.

Any advice on what formula should I put to suppress the footer A and B?