When returning the trim switch 'SC' back to the upper position, we enter the flightmode 'Cruise'. Your Flaperons will probably be a little off on the intended position for Cruise, so your plane will look somewhat like this (Zoom 10 x to make it more clear)
In order to correct that, we go to the flaperon settings.
In the main menu, go to the 'BasicsPlus' menu item, and long press 'enter' to get the 'help' page:
And scroll one down to 'Flaperon' and long press 'enter':
Now click on Go! and adjust the flaperonOffset:
The flaperon offset will correct the servo center position to have the ailerons in the neutral position for the flightmode 'Cruise'.
Now the basic setup is finished for the wing part, and we anly need to set the camber and elevator preferences for the different flight modes.