The effect of rotation is greater than you might think; any artilleryman will tell you that when precision shooting a correction must be applied to take it into account. Shooting North-South and vv the correction is entirely to the azimuth, and East-West and vv it's to the range. As you might guess, on other bearings it's a mixture.
I forget the values of a typical correction; could it have been 10m on a 35 second time of flight when shooting, say, due North?