Oh wind your neck in ffs. I don't give a toss how wiper motors work, or how you think they work. The fact of the matter is that, on my car, when you wash-wipe, the final downstroke is much slower than all the previous sweeps. Not all of them, just the final downstroke. This is not up for debate, it's a fact. You're the one spouting the #####. During normal operation, the wipers come to rest at a specific point after each sweep. When they're switched off however (or are on auto and haven't swept for a while due to lack of rain) they park themselves at a position lower than the normal operational rest position. This position varies each time they park. This is easily seen by pressing the stalk down to provoke a single sweep, they will park in a slightly different position on each successive operation.