With Forms licensing you get a history of Keys each time more add-ons are purchased. Which key is the correct key to use for including all add-ons.
I thought I was told to use the latest key but ran into a problem recently.
We had a customer buy Forms, then add on Portal, then add on Participant licenses. The very latest key was the participant key and when the participant key was installed the portal functionality was removed. Then when we went back to the portal key the participant licenses were in the portal key. But this was the original key we were using back before it had participants in it. Crazy!
There should be a big clear pointer to which key contains the entire package.