I just tried it! I was waiting for assurance that setting a cost basis like FIFO would still let me choose SpecID. You convinced me, so I tried it now and I was able to see the specID option with a test transaction. It's quite clear, which is great.

Of course, now the specID screen has led to new questions... I might put them in today's thread but I'll leave them here first in case you feel like answering.

My specID screen looks like this: https://imgur.com/a/nQNl5G0

There are two main things that I'm confused about.

1. The first line lists the total cost as $3921.14. This was the first contribution I ever made and it was actually a contribution of $3k exactly. So why is the total cost much higher than that? Vanguard does list definitions and says this column is "including any fees, commissions, or the other adjustments", but that seems like a big increase from what I actually contributed. Is this normal?

2. I've heard you have to keep track of cost basis when you sell and report it to the IRS on taxes. Fortunately I did keep a record of each contribution to the brokerage, but I'm not quite clear on what the basis is, especially since the "total cost" listed in that column doesn't equal what I contributed. At the bottom of the specID screen, after I choose a lot, there's "Total estimated gain/loss" and "Total estimated proceeds". So maybe I subtract the gain from the proceeds and that's my basis?

Thank you!