It sounds like your customer is on active duty, if she is being stationed at Fort Sam Houston after completing her basic training. So she is entitled to relief on any credit she entered into before she entered basic training. She will continue to be entitled to that relief until the expiration of her active duty obligation.
Adding to the confusion, the term "enlisted" can have different meanings. For example, "I have enlisted in the military" means I have signed up to serve in the Armed Forces. Another usage though, is in referring to those in the military that are not officers. They are referred to as "enlisted" personnel. So, unless you have some military background, I understand how it can be confusing.
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Jim Bedsole, CRCM, CBA, CFSA, CAFP
My posts - my opinions