system
5
Well for clarification just repeat the steps you need to follow for right purchase:
- you have only one google account active on your device (Play has some issues in case you have two or more accounts synced)
- validate your account is synced (mainly applications sync)
- buy the product via Play (mention, which account is used for purchase)
- receive license into email
- update your product via button Premium (if the product will not do it for itself)
- try to log with the same account you have used for purchase on your other android device
- go to Play and install the product
- you should see it as active purchase