Doctor D:
I believe the DCM uses the "counter" system to determine blockage. That's what you do when you resynchronize the window is reset the "zero" point when closed. I don't think the amperage draw is what it's using, it just sees the counter slow or come to a stop. The only one with express opening/closing that comes to mind that is different is the latest style ML I know they did a little differently, can't remember what they did on that one.

Gilly