Minor problem with Import-MT

Here’s one I can’t seem to find in the message forum. Downloaded the latest nightly. Installed without issue and logged in as admin. Exported entries from MovableType and ran import script. Told it to change all authors to the admin account under WordPress.
It imports all the entries without issue, but instead of assigning them all to the admin account it makes a new user account with the same name and attaches all the entries to that instead. So I’m now left with two accounts with the same ID with all the imported entries associated with the second account. Not sure what I’m doing wrong.