Suggestions for recurring gross-up payments through Payroll

PeopleSoft Enterprise HCM Payroll for North America - Version 9.2

Curious how other customers handle recurring monthly gross-up needs for their employees. 

For example, our Payroll team received a request to process a monthly housing allowance payment for a new hire. This normally can be handled easily by the Additional Pay functionality, however, the business's agreement with the new hire is for these payments to net a specific amount, let's call it net $1000 for housing. While the gross-up can be done easily manually on the payline (or using PSHUP), the gross-up option is not available on the Additional pay page (only in the reason drop down which does not drive anything functionally).