Hi Joden.
The PlusPak needs a full installation to work with. As I understand it, it's a package that gives all new material and is designed for upgrade use with the UltraPak.
Provided you've bought a copy of the UltraPak (or equivalent), then it's possible to upgrade year by year using the PlusPak. The new yearly PlusPak must be installed every year for this to work.
I did this for many years.... for example, I had an earlier UltraPak equivalent (I'm guessing around 2013) and then each year I upgraded using the PlusPak for the next four or fives years.
I suggest that you use Live Chat to talk to rep. and ask them. They will have access to you account information and know what you've purchased and will thus be able to advise you better than I can.
Regards,
Noel