Interesting historical trivia:
Benny Howard's DGA-8 through DGA-12 SE 4-place cabin aircraft were 38' span high-wing monoplanes. The wing area was quoted as 185 sq. ft.
Then the DGA-15 was derived from the earlier ships. Same 38' span, same chord, but now the area was quoted as 210 sq. ft.
I have determined that the difference of 25 sq. ft. corresponds to the "wing box" area - the wing chord times the fuselage width. So the difference is simply a difference in method of calculation.