You need to be careful when talking about "in spin aileron" in an inverted spin. In an erect spin, roll and yaw rate are in the same direction and thus "in spin aileron" is in the same direction as both roll and yaw rate. However, in an inverted spin, roll and yaw rates are in opposite directions and, by convention, the direction of an inverted spin is defined by the direction of yaw. Therefore, in a left inverted spin right aileron is in the same direction as the roll rate and will, therefore, have the same aerodynamic effect as left aileron in a left erect spin (and vice versa). Hence the A4 advice regarding the direction of aileron input in an inverted spin. For inverted spinning, I refer to left and right aileron to avoid any ambiguity, and I always avoid the phrases pro- and anti-spin with respect to direction of aileron input.