Addon domains - not possible

I've been working with CPanel for some time now, and this really sounds like a newbe question.

Inspite of the fact that I change a package to be able to use addon domains, it never shows in CPanel (the '0' remains) and I am not able to use a addon domain, because I don't have enough addons to use ('0').

I'm using WHM 9.9.7 cPanel 9.9.8-S6

Is there something I'm not seeing here? Why can't a changed package use addons?

Same thing with parked domains. The '0' keeps showing.

I must be missing something.