Yes, I think you answered your own question, but first, why do you have so much spoileron (up flaps)? Did it rock and snap out of elevator before putting in spoileron? Try taking some of that spoileron out and see what it does. By having a lot of spoileron in your wing, you really have to get the plane nose high before the wing will create any lift, and having to add enough power (throttle) for that, may just tumble your plane out of the Elevator.
DKjens