Merge Field to Pull Prior Month on Contract Invoice Printed Doc Template

[James Flook]

Hi,

I would like to display the billing period on  invoices. For example, an invoice was created with a date of 12/2 for the period covering 11/1 - 11/30 and would like to specify on the invoice that the invoice is for November. Is there a way to populate the prior month based on the invoice date?

I am able to pull current month on the printed doc template using MERGEFIELD WHENCREATED \@"MMMM" \* MERGEFORMAT and have attempted to pull prior month using the below without success. 

 

MERGEFIELD WHENCREATED \@"MMMM"  \-1 \* MERGEFORMAT

MERGEFIELD WHENCREATED \@"MMMM"  \-1 MONTH \* MERGEFORMAT

Any insight is appreciated! 

Thanks