That would be a standard type meeting format then.
Webinar is a term I particularly hate, and when ever any are organised at work I refuse to participate unless absolutely necessary. Apart from the bad portmanteau name, they tend to be very annoying with the first 20 minutes spent checking everyone can hear and talk back, then you get someone in bulgaria or whatever who's phone is ringing, so they answer the phone without muting their connection to the webinar, oh they're a massive pain in the rear.
and don't get me started on the people who send in orders with "20 off" or "20no" instead of "20 of"...
I think that you will find that "20 off" is widely and correctly used in many disciplines. It derives from items to be made in accordance with engineering drawings or templates. A common example is when someone is described as a "one off", implying that he/she is unique. If one is referring to a stock of products it would then be appropriate to request "20 of those".