You should but call TiVo first and ask. Typically they offer the service transfer from older TiVos to the Roamio with the ones they sell but you will just have to call and ask.
I upgraded from an hd to Roamio and kept my $9.95 plan, in fact I have it for sale too as I upgraded to a Pro and they won't allow me to transfer it to the Pro.
TiVo Roamio Pro
TiVo Roamio Plus (3tb)
TiVo Mini (three)