VERY sorry for the delay in responding!!! yup, by the sound of it, you gave it MORE DOWNthrust. look at it this way: with the stock airframe, the motor already has a considerable amount of DOWNthrust.
remember, unlike a helicopter, the motor on this airplane is pushing air out the back... setting the prop so it's more like a helicopter will make the prop blow the airplane DOWNWARD.
looking at the motor / prop from the side of the airplane, you'd want to make LESS of an angle between the prop and the airframe centerline. (you'd want to decrease the motor's angle)
if you visualize this while looking at the airplane it should make sense, but DO feel free to post back if you're at all in doubt.
sorry again for the delay in responding!