Be ing the pica kit, you could have sanded the leading edge a little different and the incedence meter is picking that up. The difference is so little on that bird that I think it should be fine. Plus, after you cover the bird, you can always twist it back.
Heres how you figure out what is going on, write down the numbers as you go.
1- bolt the lower wing in place and take a measurement from ground to wing tips (make sure the fuselage is level in the horizontal plane)
2- bolt the upper wing in position and take your measurements from ground to tips and between the two tips.
3- put your interplane struts in and recheck your measurements, if they have changed, the interplane struts are inducing the twist.
If it is showing up in the lower wing, then it means the the top wing it torsionally stiffer than the bottom wing. But if when you take your measurements and find out that the lower wing is off, and nothing else is attached to it, then that will confirm that the wing has a slight twist to it, providing the saddle is even and true.