In which case there's no reason you couldn't have V6, but it also depends on your contractual status - whether you're in or out of minimum term dictates how strong your "please can I have" position is.
Calling in may be the quickest way here.
You should also be aware of the possibility of a sales job on the new TV360 being offered. It's VM's latest TV software and is very different to the TiVo platform you're familiar with. One major caveat in your case is...
If you convert all 3 of your TiVo to V6, they retain independent hard drives and have multi-room streaming.
If you went the 360 route, you will only have one master box with HDD, the other 2 boxes become minis which slave all recording from the master.
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