iTunes Match - 2 Apple ID's, 1 computer

I have been an iTunes Match subscriber since it was introduced in the UK.

My wife has decided to join too.

We have one laptop in the house with all our music on there, and we each have our own Apple ID's.

When she went so subscribe, the following message appeared;

"This computer is already associated with an Apple ID

If you subscribe to iTunes Match with your Apple ID, you cannot use iTunes Match auto-download or download past purchaseswith a different Apple ID for 90 days"

The options are "TRANSFER" or "CANCEL"

The computer has been associated with more than one Apple ID for many years, why is this an issue for iTunes Match?

If she chooses to transfer will everything be ok after 90 days?

What will happen to my Apple ID?

Please help.........................................................