If you are active military, one of the enlisted grades, then there is no charge for using the TurboTax online editions (except Live). You must indicate you are military in the My Info section and enter your grade where asked. You are required to enter a Military W-2 to be eligible.
See this TurboTax website - https://turbotax.intuit.com/personal-taxes/online/military-edition.jsp
And edit that W-2 again too...on one of the pages after the main form, there is a long list of checkboxes...there is one in the middle that needs to be checked for that DFAS W-2.
That checkbox doesn't show up unless you properly indicated you were in the military during 2020 on the My Info page.