I have retracted what I said in post #6, after talking to both companies today.
That tank, that Cruco said was NOT a 160, according to Praxair, is a 160 (and yes, out on the dock, in the 160 area, there are about 4 different tank sizes, but they are all loaded to 160cuft). Praxair won't buy back tanks anymore, so I just got an exchange.
Cruco...I would have just kept the 2nd tank, I was thinking about buying an 80 anyway, but when I got it back to my shop on Saturday and hooked up the regulator, it only had 850psi in it (should have been 2000+). That happens, have had it before (bad valve or whatever). So I took it back...Told the guy about the Praxair deal, and how they (Praxair) wouldn't buy back tanks anymore...so he offered a full refund on my Saturday tank.
Both, IMO, still good to deal with. BTW Praxair (CWIS) has lowered exchange price. It was a few cents under $35, Cruco is $35. Praxair was $50 last year (I guess that might vary, and they are all up and down about the same?).