Thanks for your reply!
I tried to google it before, but only found really old posts, not the one that you showed me.
Regarding your question, let's see if I can make it more clear (as I do read it back and think, huh, that isn't perhaps the best way to get my point accros).
I'm about to go into the Premier League and my board keeps rejecting expansion due to the finances. Playing LLM and whenever I sell a player for a lot of money (usually got them on a Free instead of a transfer), they keep adding my profit to my transfer and salary budget. Which is off course nice as I'm able to add better players and a lot of youngsters to the squad. But it does mean my bank account is quite empty at the start of a season. In 3 seasons, the board accepted an expansion once. So building a new stadium, is going to be a big no for them. And tbh I rather keep my old stadium's name and just add the "Expansion Capacity" to 60k instead getting a weird stadium name in return with a newly build one.
I meant here to ask, if you have more attendance than seating, is this the trigger for FM to let a sugar daddy / Board with a wealthy bank account allow for a new stadium to be build? But you already answered this with your Newport vs Man Utd example :).