I see those options as 2 different things. If you want to convert company dollars to Roth, it's now a taxable event at tax season and you aren't adding actual dollars of your own into the plan. Total balance remains unchanged. If you ADD money via 401A with immediate conversion, you still pay taxes on the dollars going in, yet the total balance is higher as more dollars are actually going into your plan. If you were to contribute 17% via 401A, while the company is also contributing the 17%, in theory your 401K bucket would hit $69,000 with $34.5k as ROTH and $34.5K as taxable (all company contributions are "traditional"). So now you have $34.5k vs only $23k (Roth 401K limit) in the account. After that MBCBP gets 17% from the company. Keep also in mind that if converting "in plan" you will need to call fidelity each time you want to convert. If having 401A contributions immediately convert for Roth it's a single phone call and done. Speak with your own financial advisor to figure out what works for you, but if creating a 3-bucket like strategy there are some strategic moves that can be done in the earlier years so you don't have to play the Roth IRA conversion game in retirement.