If you’re running New Emperor, for example, which contains its version of the NSE and you add a title that currently doesn’t have the NSE, that title will be affected to an extent by the scripting in New Emperor. But, like everything title we create, all of the scripting in New Emperor is designed to fulfill the goals of New Emperor first and foremost.
So, the 100% optimal way to get the NSE to affect EVERYTHING is a standalone version, that “sits at the top,” so that EVERYTHING is filtered through it. This misunderstanding comes from the notion that the major titles are just collections of modules. It’s not true – Nouveau R.I.C.H. and New Emperor, for example, are pretty much completely brand new scripting. The objectives may be the same in New Emperor’s case, but I started from a blank canvas and started writing based off the latest ZP playbook.
The NSE in New Emperor is very much tailored toward the goals of New Emperor, but if you added True Sell, for example, that wealth scripting would be affected as well. But this core is intended to “sit at the top” and filter EVERYTHING through it.