USAF? USA? USMC?  

Reread the exchange. It was predicated on where someone would be after 12 years of service.  I gave pay for CW3 and O-4 (the likely rank achieved at 12 years service) and 10 year ACIP. 

BRS is not like a 401k.  BRS still uses the retirement annuity formula that has been in place for years, it was just reduced by 0.5% The formula is now 2% of the average of the service member's highest 36 months of basic pay x the number of years of service.  The offset is made up by a montly 1% of base pay contribution into TSP irregardless of what the service member puts into TSP.   TSP also has the no risk G fund option.  I have never seen a no risk 401k.  Either you are unclear on how BRS works, or how 401k's work.  You may want to check into that if doing any retirement planning.  Your PRC probably offers no cost financial counseling.  

BRS did not go into effect until 2018.  For the purposes of this discussion of "where would someone be after the 12 year commitment was up" they would still be under the old retirement system Since they would have entered the service in 2011. They would still be under the 50% plan.