Aetherflow is always 20%, regardless of MP pool
Shroud of Saints is not

If you have 4300 MP, Shroud of Saints would recover 24,65% in comparison with your MP pool
If you have 4600 MP, it's 23,04%
If you have 5300 MP it's 20,00%
If you have 5500 MP it's 19,27%

Oh look, you are right on one specific MP pool that will no longer be correct the moment you're at 5299 or 5301 mp. You can't associate Shroud of Saints with a certain percentage. Simply because it does not scale with your MP pool. You make it look like it scales with MP because you're using the level difference, but that's because Shroud scales on level, not MP pool. Obviously, if your level increases, your maximum MP increases as well. So that fabricated information of yours isn't even complete.

Also where's that 100 potency coming from? Shroud doesn't even have 100 potency. If you're "predicting for Heaven's ward", Heaven's ward is now not relevant at all.