Q: from the IRS chart, I see:
Roth IRA Designated Roth Account
Contribution limits $5,000 / $6,000 (if age 50 or older); $16,500 / $22,000 (if age 50 or older).
The question is: is this $16,500 in addition to the TSP limits OR does this include the current TSP limit?
I.e., I'm maxing out my TSP limit of $16,500/year; is this $16.5 of Traditional IRA plus an additional $16.5 of Roth?
Upon reflection, It looks like instead this would allow me to characterize some part of this money as Roth money but doesn't change the overall amount pointed to retirement goals. So what the TSP Roth option appears to offer is a way to put money in the TSP funds that is treated as Roth once you withdraw it.