I don't remember what company I used, but the last time I had tanks hydro'd by a fire extinguisher place here in Tampa, but they didn't dry them. By the time I got them to my dive shop to be VIP'd/filled (less than 24 hrs) they all had to be tumbled to remove flash rust. This negated the cost savings, not worth the hassle.
Here in MD going rate for Hydro / VIP / Fill is about $50+ tax. When you have 15+ tanks, even a little saved is worth the hassle. By doing my homework and a little elbow grease I've managed to chip that down to $35 flat and it's at a shop that does know the roundout procedure.
+$225 in my pocket..... with which I guess I can buy more tanks!