Just to update you that I've tried what you suggested, and it works. Strangely, the screws did not seem loose when I took the PZ2 to them. But when I turned the driver 180 degrees and re-fitted, the problem seemed to have vanished.
I'm just left curious and wondering what could've gone wrong!
In any case, I have sent my serial nos. to your company e-mail. Here's extending my gratitude, and for the record, I truly appreciate that you take time out to personally reply to our posts. Your views are both insightful and enlightening.
Thanks once again.