Dialing extension, one biggest hassles, never been able to figure out how to do the auto trick. This links explains ok:

https://www.payetteforward.com/add-an-extension-to-iphone-contact-heres-fix/

Finally worked with one bank, but then another bank did not work. not sure why not.

Not sure matters at all but: can you put comma in phone or desktop version of contact same/ ok? Can put comma in with keyboard comma or have to be the + method with iphone keyboard only? o r not matter? Is odd or normal works with some places not others? Any others explore this? thanks.

I'm not sure if I can address your specifics, but what I have found is that the success or failure of adding commas depends on the phone system to which you are calling. Some systems require the "+"; but in those that take a comma, the comma represents a pause. How long should the pause be? That is, how many commas? Depends on the phone system. Some respond immediately, others require the outgoing instructions (e.g., if you know your party's extension, enter…") to completely end. Annoying, but if you listen and try varying amounts of commas (yes, requires repeated calling), eventually something should work.

Ira, thanks, never knew of thought about this, so that why I'm posting. Don't even know if much info on this online.

You saying that if one company does not work add another comma? So two commas in a row? Or three?

Yes, you can do multiple commas in a row.

Ira, thanks, will test 2, , then 3 commas... ...