This ECU has a very strange operating Logic.
I have done stage 3 with td04 , but I do not like it as fiat 1.4 T-Jet with Bosch ECU.
I am searching for the solution ( I need for 620cc injectors) i will let you know
on tjet which has me7.9.10 ecu, that injectors need fkkvs adjustment.
i can help with KECH for you on 8gmf, linearising injectors but i didnt try to adjust like fkkvs yet on these ecus. there is a map called TBAIRCANTURBO which is for "Table for the air flow through the enjector tee, function of tank pressure and Enjector Tee inlet air flow" maybe that can be the catch for like fkkvs there