They used a useless feedback option for Bf-109 "HUD" indicator for flaps, radiador and prop pitch, (and bomb bay in some planes) rather than show how % are open, or if are full open or full closed - like in others planes - only tells if command is pressed "Up/Down" or in "Neutral"...
A possible workaround: use HOTAS soft (or NewView) and program keystrokes to act for XXX milliseconds, so you dont need watch until flaps go full down.
This allows too "cheating" creating a command for "combat flaps".
Sokol1