Sounds a little odd. If your time counts toward retirement, it would take 5 years off the amount of time needed to retire. I know several AF Dentists that were active duty enlisted and that time counts toward retirement. In other words, if they served 5 years on active duty, they only need to serve 15 more years to retire. I think you need more clarification and maybe need to talk to someone with more knowledge.
With all that being said, there are some other issues that can arise. Did you have a long break in service? Was you enlisted time in the Guard or Reserve? I served 9 years enlisted in the National Guard. That time counts toward pay, but only the time I was on active orders counts toward retirement. So, out of 9 years I had about 6 months active time. So I have to serve 19.5 more years to retire, but when I do I'll be paid like I've been in 29.