Number of membership types

I have created 7 types of active memberships. But, i can only see 4 of them. Why?

Are all seven actually active at Admin > settings > Membership Levels > Manage Membership Types

All are active, But only four are displaed when a standard member want upgrade.

The default 3 levels won't show  ..... 

i.e.

Non-member
Standard

Promotion