It is rather strange that you ordered a 24x drive and they sent you a 22x drive!
Based on the ZL0C firmware you've got, I believe your drive is a B series drive and that you can indeed crossflash it to an iHASx24 B drive. Dump your firmware using the Flash Utility and post a copy in here. I'll have a look at it and I'll then be able to confirm 100% that your drive is indeed a B series drive as I think it is.
I don't think that's correct.