I have a question for the aero engineers/test pilots on the List.

The airflow over the top of my wings flows inboard, not outboard, or
spanwise as I have been led to believe is the normal case.  This inward
slant of the flow is indicated by the flow of residual grease from aileron
hinges and traces of lubrication I put on my gas caps.   Both wings are the
same.  The inboard angle is not great, just five or more degrees roughly if
I were to measure it from a point on the leading edge to the trailing edge.

1.  Is this normal for the 320 wing?
2.  Is it a good thing, as in less drag?
3.  Do other flyers notice the same phenomena?
4.  Why is this happening if we are to expect spanwise (outward) flow of air
over the wing?

Are these dumb questions?

George Shattuck
N320GS