Slice Security - Data Cell Access

I am not positive but typically I start with the first slice by either a) removing all access to all users, then slowing adding it back slice by slice or b) grant all users access then removing it from only select slices of users.

For example if your first slice is like this which would be A)

Then subsequent slices would add back or increase U1 access for different BUs like this:

So in a sense choosing Apply vs Increase vs Decrease may depend on what you have granted in prior or subsequent slices.

I typically start by removing access (Apply No Access) for "Everyone" then in then in the next slice increase access for anyone that has READ or WRITE to everything (Increase to Read Only or All Access then continue) in the UD. Then follow up for people who are not in the "everything" meaning they currently have no rights (per first slice) and are not allowed to read or write everything (3rd slice) start adding back in different slices based on different user groups (Increase to Read Only or All Access for a subset of the UD) and so on.

Not sure if that helps but I think Apply vs Increase vs Decrease is in relation to prior or subsequent steps.