Here what the current sensor reports. I did some change the code to put the monitoring of current into a file to understand how good the initial calibration is.
Here how it looks like when the shutter is calibrated. On the x-axis there is the time since it started to move. Watch the end. To me it looks like it is slowing down at around second 37 then really mechanically stopped at second 39. Then the shutter detects this, turns back on its own to release the mechanical pressure at second 42, then finally shuts down on its own. From there on a very low current can be measured.
Second, when doing timing based up/down the up/down end positions will move likely. Having the current should make that obvious. Lets see if this kind of sophistication is even necessary.
Check this file to see more data: