key flex field security in R12

Hi:

I am not sure if this is the correct forum for me to post this topic. I want to understand the key flexfield security in R12.

We are using EBS version 12.2.4

I have found a note in this website regarding the security for flexfield value set. I understand that I can create role and grant to get users to be able to insert and update certain value sets. However, what about values?

When I create the grants, I see three options listed, all row, instance and instance sets. I now understand that instance sets are for value set. But what does all row and instance option do? How can user maintain values and maybe not necessarily value sets? Is that possible at all?