Grade Step Progression retro pay where position/grade has changed

Summary:

Content (required):

I'd be grateful for advice on if/how a certain scenario we're facing can be dealt with (or if the only option is manual changes). Our grades have several fixed steps, lets say Grade A has step 1 £10,000, step 2 £15,000 and step 3 £20,000. We will be running the grade step progression process to move employees up one grade step, but this will be backdated to 1st April. In most cases, that's fine and retro picks up the backdated pay that's due.

If an employee has moved positions since 1st April, the process is not working as we'd like. E.g. Employee A was in a Position at Grade A step 1 but on 1st May, was promoted to a new position in Grade B. Due to the backdated pay step progression, for the period 1st April-30th April, the employee is eligible for backpay based on Step 2 of Grade A (as they were only paid at Step 1 at that time). The Grade Step Progression process is errorring for Employee A due to the change in Position/Grade and so no retro pay