I'm doing something wrong.

I want:
Plan A - $60 no more upgrade options
or
Plan B - $30 with the option to upgrade to Plan A for an additional $30, but not pro-rated.


I have two separate plans with no parents.
I have Plan A set to exclusive, allow upgrades
I have Plan B set to exclusive, do not allow upgrades

When users select Plan A, they still have the option to "upgrade" to the same plan.
1) how do I get rid of this upgrade option?

2) how do I set up Plan B, so require only an additional $30 on the upgrade?