Actually, as cmoulder said, most planes tend to nose down in pitch with flaps down. If you've ever had a flying wing, think about how that worked when you dropped both elevons! Now, in case you're setting yours up and want a first crack for flaps &spoilers- I am only at 13mm on flaps and the up elevator mixed in with that is just a mm or two, something like 10% mix with my linkage geometries.

Or were you surprised I could program it? That takes a bit of trial and error!!!! I have yet to see a perfectly clear programming manual for a radio when it comes to flaperons and spoilerons- always double check what they said should do what mix!!!!!