@dmg86 yes I effectively did but it raises more questions. The answer for me is (and I checked on my wife's account too, different company/401k provider) simply they don't let you take out a loan on the Roth portion of your 401k. The pool of money I have to take a loan from consists only of the pre-tax proportion rather than the full amount in the account. In other words, if I had 100% of my 401k money as Roth contributions + earnings thereof, I wouldn't be able to take out a 401k loan at all per my company's (and my wife's company's) setup.
I suspect this is actually a rule since two completely unrelated companies with giant 401k managers (I'm not sure what you call the company that actually facilitates your 401k but one of them is Schwab) wouldn't likely have this action forbidden if it weren't a law. But it could just be one of those things where some places let you do stocks and options in your 401k and others don't. My original question was trying to understand what loan paybacks are categorized as, but it looks like if that one guy is right, they're categorized as earnings, which to me both doesn't make sense and would mean you're double-taxed on them, as you would pay taxes on the money used to pay them back and then pay taxes on everything you withdraw from a traditional 401k, if that were the case. I'll see in a few years though, I took out a loan just to see what would happen and answer this question for myself. I'll try a Roth conversion at the end of the loan so I'll be able to see exactly what is counted towards what.
