One more question. As upgrades are cumulative, How will it works if a player buy 10 upgrades at the same time ? You will have to pay him 10 times more, but he will not generate more ad revenu. It could put you in red !
That's why i keep suggesting (about inventions) that
no more than 2 inventions should be allowed for each player.
I have only 2 active inventions and i stopped to get the 3rd just because i care about virtualpub (admin can check my account to see only 2 inventions and im registered since day 5 after launching ..i could have 10 inventions by now

).
I hope admin take notice and analyze my suggestion asap for virtualpub stability.
If there is no idea how to do that, there is always a way, even if the inventions system needs to be reset and/or deleted and start finding new ones but this time the script should allow only maximum 2.