I had 630cc Siemens Deka at some point and my idle was simply awful. The 20v motor does not like the Dekas. At this point he was trying to fix that for me and I assume this change was part of that and he simply forgot to bring it back once I changed the injectors with correct ones (630cc Bosch 0 280 158 123, dual cone spray pattern). With these the idle is 100% stock.

Unfortunately I will never know, my tuner passed away not long ago, may he rest in peace!