I just looked at the specs of the actuator that you quoted early in the chat. In my 'guess from experience " the 10% duty cycle indicates a current restriction. The force available seems low, particularly in flight. The dynamics of how the actuator forces the flap could produce a larger force than the quoted figure, try the current test on the ground, then loan flap with hand and see what happens. I am like a pig in mud, I did this style of investigation before I retired, loved the work, these days I just wish that I was not retired.