If we change the l10n values, then we need to change the key names too. So maybe something like "new-emails-notify-one-account" and "new-emails-notify-multiple-accounts" Otherwise the l10n tool will not see the changes.

Since [bug 919004](https://bugzilla.mozilla.org/show_bug.cgi?id=919004) also has string changes in this same section, how do you feel about just doing the changes for that bug in this changeset too? That will mean we only will have one l10n update for those two fixes, which should help the l10n teams.