Alpine Takayama matsumoto area pass follow up question

I don't think you can ride the shinkansen using a pass and pay for the price difference.

at least I have never seen anything like it during all of my travels to Japan. Passes have special-set prices and they wouldn't be able to properly calculate the price difference.

you would need to buy a shinkansen ticket for this.

In the title you mention that it is a follow up question, was it this one?
alpine takayama matsumoto area pass
https://planetyze.com/en/japan/forum/japan/travel-tips/alpine-takayama-matsumoto-area-pass