oh gosh, the ol' fowler and slotted question... I got that on my checkride "Son, does this plane have slotted or fowler flaps"
Anyway, the pitching moment seems quite plausible due to an increase in drag. By the flaps extending and moving downward, you are increasing effective surface area as well as angle of attack. You'll also get a big increase in lift at the 0-10º transition (wich is why in the 152 10º are used for performance takeoffs).
In any case flaps are cool.