Convert to title case - but then want to make case changes without it forcing back to title case?

I have a very large document where I need to correctly set the case for chemical names, which have their own form of capitalization rules. An old program had chemical names in all caps (very wrong!) that I have been tasked with correcting the case of. If I take my Numbers column and convert to title case, I go from:

P-CHLORONITROBENZENE to:

P-Chloronitrobenzene

But now I need to correct the name to:

p-Chloronitrobenzene

However, if I do that, the p- automatically capitalizes. If I remove title case, my 77,000+ chemical names revert to all caps.

In excel, I would set the chemical names to lowercase, then copy and paste, and the converted text would paste and the old style would be gone forever, and I can freely change whatever letters without it being auto-changed. Can I do this in Numbers?