Yes, I think you're correct Mr eagle: my mistake. Though it doesn't make much difference to me since at the moment since I suspect, like many other MTO3s at the top of the grade, I'll end up on the penultimate increment on AfC Band 5 with R&R protection to make my wages up and protect my future pension long-term until I leave anyhow.
This means zero pay rise under AfC for me, hence no back-pay, so I guess I'll be relying on the 3.225% from April then, on the old pay system. The back-pay dilemma I've described is only an issue if one actually gets placed on an AfC band with a higher salary than one is currently receiving.
If I were inclined that way I could suggest, perhaps, that I will likely have my nose rubbed in it, so to speak, if the majority of my 20-odd colleagues in the department where I work (who are now either in managers, specialist or supervisory roles after a recent reshuffle-squared) are placed on band6.
I suppose that I'll have to be a good-boy and wait for my back-pay due under the old system and accept my lack of "rewards" in the new system (plus limited future prospects and effectively frozen pay comparatively speaking) until "they" are awarded their increments onto the next higher salary, than they are currently on, on AfC band6 and receive their back-pay on the old system plus extras for on-call of up to 10% of salary.
Now there's a thought.