Do you have another level you can put your meter on and check IT. The meter may not show -0- when level.Ken
I have a plane with a SIG Super Chipmunk wing un-covered, I'm just aligning everything and ran the incidence meter the length of the wing, it has 1.5 degrees of negative at the tip when the plane is upright but when inverted it's dead on zero. The leading and trailing edge looks straight so it's a head scratcher.