At Schwab, if you do Roth conversion by selling in TIRA, transferring the proceed to Roth IRA, then buying, there will be fees as applicable for buying and selling.
Instead, you just earmark
n shares of
X stock to be transferred, or all of
X stock or MF. You just keep selecting more stocks/MFs until you have enough in total dollar amount that you want to pay taxes on, which is based on the present values of these shares as if you sell and rebuy. They show you the running total as you keep adding. Then hit transfer.
There is no fee with the transfer-in-kind as above. I have not withdrawn from IRA into an after-tax account, but imagine it will be the same way.
Then, at tax time, you get a 1099 confirming the dollar amount to declare to Uncle Sam as income.
PS. I was shown the share values in real time quotes for stocks, and the last day closing NAV for MF shares as I did the Roth conversion. Just now, wonder if the official dollar value reported in 1099 was updated with share prices at market closing of that day for either MF or stocks. I did not write down the values to compare with the 1099 later to see if they changed by the small fluctuations of that trading day. This price change is small and not material, but I just now wonder out of curiosity what the IRS allows.
PPS. If one cuts really close to the ACA subsidy cliff, the above detail becomes important.
I would not come that close to any cliff.