I just wanted to add on to this post, in case others are in the same boat as far as trying to enlist as 18X as E-5 or above.
My recruiter completed my grade determination waiver, and even though he was absolutely convinced that I would be bumped down to E-4 (since I've been off active for 6 years), the Army gave me E-5.
Now, I just happened to have a super helpful recruiter who really went to bat for me, so he pushed for a waiver, and I officially signed my 18X contract as an E-5.
So with mine and Tsircou's situations (at least as of Feb 2014), it is possible. It takes a lot of red tape and your recruiter has to pull strings, including getting SF recruiting involved, but if you want it, it can be done!