Hi and welcome back,
I don’t believe what you’ve described possible at this time. In my experience, changing that setting at all after the site is live is probably not a good idea because it can apply retroactively. For example: say you have sold 50 tickets and decide to switch from including the fees in the price to tacking them on. The amount shown paid out to clients for those 50 will be different from the amount actually paid out.
Just some strange oddities here. And I don’t see a great way of working around those oddities to implement per event pricing. Sorry I don’t have a better answer for you and in these instances, I like to recommend submitting your request to our UserVoice Feature Ideas page. Best of luck and have a great rest of the day!