BJ reminded me that I left out part of the story.
The driver's side window was repaired and, two years later, it fogged again. Two theories.... Our Beaver had a flaw where the window frame was crooked that put that window "in a bind" that caused repeated failure. The other is that double pane windows can't survive the combined effect of altitude and temperature change.
RV Glass Solutions offered to fix the failed window at no charge. They offered us a choice. We could have a custom cut single pane of safety glass or a third try with dual pane. It was explained that they wanted to experiment with having an option for people that wanted a permanent repair. We opted for the single pane.
When we sold the Monterey there were a lot of fogged windows and it effected the price. Had we kept it and repaired the windows, I'm pretty sure I would try to get single pane. One of the "features" or our new (and very small) motorhome is that it has single pane glass that will never fog.