Membership Type isn't updated when user's account / role is changed

Issue Summary

hello
first off just want to say how great this module is - thank you!

ok my problem is this:

i have 3 membership types

• candidate
• registered-user
• subscribed-user

which are tied to 3 different accounts

• candidate
• registered
• subscribed

and 3 different roles

• registered candidate
• registered user
• subscribed user

each role has different content creation access, like an upgrade system. ie candidate cannot post content, registered user can post one content type, subscribed user can post all content types.

i have allowed the administrator access to changing other users account types (from candidate to subscribed etc).

however i have noticed that once a user logs in after the administrator changes their account type, the membership type in their general / account seetings does not get updated.

any ideas on why this might be?

thank you in advance
cnp