No. You have an initial 8 year military service obligation (MSO); this can be served in any form of service, active duty, drilling reserves or IRR. Lets say you enlisted for 4 years active and after 4 reenlised for 2 years...the got out. You will still have 2 years oo reserve time.
Lets say you did 4 active, re-enlisted for 4, then for 2 then got out. You would have no remaining MSO.