Lack of interest Option for managing "Last username change" when user a merged

[Kruzya]

Currently, when user X merged into user Y, Y can lose ability change own username, because XF updates the last date to current timestamp, when he changed own username.
I suggest add option or checkbox on form with merging user for just updating "Last username change" to value max($a->last_username_change, $b->last_username_change) instead of \XF::$time.