Ah yes, the POS kitchen aid dough hook...
IMHO both you and luigi are correct. By holding back 25% or so of the flour, your dough should have a wet enough consistency to actually be kneaded by the hook. You are looking for the hook to work thru the dough so it needs to be wet enough to even stick to the sides of the bowl some. This is where the actual kneading takes place.
Then as you add the remainder of the flour the dough will begin to climb the hook and begin its tilt-a-whirl ride. At this point, and as I continue to add flour, the ball climbing the hook will appear wetter on the top than at the bottom. So I remove the ball, turn it upside down, then continue adding flour. This ball removal and reversal may have to be repeated half a dozen times or more before the last of the flour is incorporated and the dough is smooth and an even consistency.
Whatever you do, do not increase the mixer speed in an attempt to fling the dough ball (or portion thereof) off the hook. This is way too rough handling and will result in a most tough and chewy crust. Been there, done that.
At least this is the best method I have found. If there is a better way short of buying a new mixer I would love to know how.