Injectors are different for a start, turbo geometry is different aswell, therefore VNT control maps are different, and there are other software differences too. 038906019NT is the
Cupra TDI BUK ECU, and your FR is probably the 038906019NJ BLT ECU, both have different injector duration maps and these work hand in hand with the Start of Injection (timing). Basically, it's not the way to do it.