To be frank, I think I would fail that auto-type feature also. Shortcuts shouldn't interfere with long-cuts. People do things out of habit and you shouldn't add shortcuts to disrupt those habits. If they enter the full email URL, then the auto-appended part should be parsed off internally, or better yet: automatically disappear once "@" is keyed.
K.I.S.S. often overrides saving keystrokes when dealing with wide or unknown audience.