ECU downgrade issues

[Nefton]

Hi , I have an a7 from 2015 (315hp)and I wanted to disable the ad blue system which was causing problems. I went to guy and he disable the ad blue to not show on the dashboard anymore but to do this he changed my ECU to a 2013 A7 (313hp). He told me that the ECU are the same on all models from those years. I said ok at the time being but now the car is not running as smoothly as it was before. It also have some misfire from time to time and it feels like is choking and rough running. Can anyone explain me if what this guy did was correct or there is compatibility issues. ? Thanks 

[Magnet]

Hello Radu, 

Unfortunately, I cannot help you with this, but I would suggest you get a local independent specialist opinion without delay. 
Re. the Adblue delete:- does this render it no longer ULEZ compliant ?? 
Kind regards,

Gareth.