Adding offset day as -1 on contracts

Hi All,

We want to update existing contracts by adding offset day as -1 on contracts with "Arrears invoicing" in order to get the invoice dated at the date of the "end date" of the contract.  We found that if the contract is billed "quarterly" for example, there is an error message and the update can't be done.

There are some of the contracts which needs to be modified. What can be done for this.

Find attached screenshot for this.

Thanks & Regards,

Gaurav Joshi.