Hi A19 and welcome to the forum.
There is no need to hang on to your Tivo as you can transfer your recorded programmes over to the new V6 box once it has been installed. (You do need a package with a connection speed of up to 50Mbps for a V6 box to work.)
As JD66 says, as you only have one box at the moment then having 2 boxes will increase the amount you pay. If you just swap out your Tivo for a V6 then it may be possible to negotiate any increase in the amount you pay.
I wasn't happy about the activation fee and managed to get the same amount credited to my account along with a couple of extra tweaks which gave me a nice reduction to my phone charges, being out of contract is useful, as is being ultra nice.
