Tax Profile Button missing in customer screen

Hi,

Earlier in one of the test instances when I log in to EBS -> Customer and Supplier Maintenance" -> Sites,  I could see a "tax profile" button on the screen.  This was used to open a tax profile screen to tag tax details to a customer site. 

In another test instance I found that the a "tax profile" button was not visible. 

Finally I did the following steps,

Navigate to Security-Admin-Menu.

Add “Customers Function Security Menu”

Now the "Tax Profile" button was visible to all users.

I checked with the first test instance and found that "Customers Function Security Menu" was available but in the second instance it was not.  Both instances were created using the same basic setup.  Why does this happen?