ok understand, in fact there is 2 points to take into the account:
1) setups have been done quickly and must be adjusted, the std F1 2015 can be adjusted in OSP factor
and the ALT F1 2015 can be adjusted in both OSP Factor and the custom shiftlights using the absolute method and editing the shiftlights curve. Attention, This take time to have a good curve so be patient if you try to match the F1 2015 steering wheel.
2) I'm waiting for the new API patch (including a fix for Yellow/Blue flags and other cool changes... ).
Also, be careful the F1 2015 engine rev limit is about 13500 RPM BUT! the gear change is around 11800/12000 RPM MAX! so do not compare the MAX RPM to the REV Limit, you should see the onboard video to understand that the F1 driver in 2015 cars do not exceed 12000RPM when they shifting
A good way to see the behavior of shiftlights is to choose the flying lap with F1 2015 setup activated. Everything is correct here, to test the shiftlights just set the automatic shifting to ON and setup SLIMax Manager SIM Race F1 setup to F1 2015 setup and this should be ok AS IS or with minor OSP adjustment
Hope this is helps?
feel free to ask if something is unclear?