Ability to use Salary HDL load while on Progression Grade ladders

We switched to Progression Grade Ladders over a year ago, and at that time we were told we should no longer be using the Salary HDL load and use the grade step sync process instead. We do not use automatic grade step progression because this does not work properly around our organizations step rules, so we have been having to do a great amount of manual syncs.

We are looking to see if we are actually allowed to use the Salary HDL load while on progression grade ladders for Across the board salary changes (retro and current) and if we do, what the impacts would be keeping in mind that we do not use the automatic grade step progression process.