PDF Invoice installed but not showing in Pay Plans 3.7 Apps Tab?

Hi Si Team

I have installed the PDF Invoice from the Pay Plans App Store.
As suggested here:
https://stackideas.com/docs/payplans/administrators/welcome/workflow-of-payplans
I believe that I installed the latest version.
I think it was 3.6.3 or similar

Surely I should now see this in my Apps Tab?

Pay Plans>Apps

There I currently see:

Easysocial Profiletype
Notification Emailer
fastspring
Offline Payment
Paypal
PayPlans-Registration-Quick
PayPlans-Registration-EasySocial

Am I missing something or has something gone wrong?

kindly advise

Paul