When I originally ordered the parts, I ordered both a driver's and passenger's side pivot arm as I was told they were different part numbers. When the package arrived, only the driver's side was included and even though I was charged for the passenger's side, it wasn't in the shipment.
A call to Tiffin and they shipped out the passenger's side pivot arm which I received today. When I looked at the part, part of my confusion lifted while yet another cloud descended. Here's a photo of the two parts side by side, passenger's side pivot arm is on the left, driver's side on the right:
The passenger's side pivot arm I received today looks just like what's currently on the MH. The driver's side on the right, in addition to being a totally different configuration with different dimensions, also appears to be missing some parts.
Even I can now see how the new pivot arm will mate and seat with the new wiper arm. What I don't know is what's the deal with the driver's side pivot arm I was sent.
I'm going to send an e-mail to Tiffin with the photos and hopefully get this squared away first thing Monday morning. And here I thought I was leaving myself plenty of time to make this repair before my next trip ... !