Tree, I suspect there may be a wing rigging setup error with that model. Provided you measured it right a 5 degree difference between the top and bottom is a LOT!

Is [link=http://www.chiefaircraft.com/cgi-bin/rcm/hazel.cgi?action=serve&item=/Models/PowerAirplanes/ThunderTiger/TTTigerBipe40.html]THIS THE MODEL?[/link]