Actually, the difference is more like 75000AED per year from A-scale Captain to B-scale Captain. The FOs that joined on A-scale then upgraded do in fact go to the A-scale for Captain. Fair enough - or it wouldn't be too much of a raise from A-scale FO to B-scale Captain! They joined under those terms. I also never want to see anyone pulled down - we should all just be raised. In other words, be happy that the guys on A-scale have what they have, just wish for it and ask for it for all, as precedent exists.
That said, I am not an A-scaler (but certainly wish I was!).