Commas after prepositional phrases?

[Elliebird]

I have been told that in the two sentences that follow, commas must be placed after each prepositional phrase because they are nonessential. I would have used only two commas in each sentence, before and after April 20.

Are these correct? They just don't look right to me!

Join us for coffee and tea in the library, on Friday, April 20, from 10 a.m. to 11 a.m.
(comma after library?)

Join us on Friday, April 20, at 10:00 a.m., in the library, for coffee and tea.
(commas after a.m. and library?)

Thank you for any insight you can provide!

[Tdol]

There are too many commas there for my liking. I'd do the following:
Join us for coffee and tea in the library on Friday, April 20, from 10 a.m. to 11 a.m.
Join us on Friday, April 20, at 10:00 a.m. in the library for coffee and tea.

[Elliebird]

Thank you very much, TDol. That is exactly how I had it before the "proofreader" added all those extra commas!
I appeciate your input.