I really doubt that ROM, AND or AND2 devs ever touched OCC, FinalFive and High to Low

All the more reason not to trust it then - Base BTS it only increased the city's National Wonder count by 2. So if they never touched One City option, then you'd
still only be able to build four NW's - making it that much harder to play with AND's large bundle of National Wonders. Well, you'd just have to put lots more thought into what buildings you are going to need. Treasury, National Mint, Wall Street, Secret Army Base, the Rubber/Aluminum Factories, Heroic/National Epics... Lots more than just four useful National Wonders, and if OCC really is unchanged from BTS, then that could be a problem.
I'll have a look though, see what it's really like.
When in doubt, play your OCC with "unlimited wonders" on , and voilà, problem solved.
Doesn't that only affect World Wonders though?