Ya'all are wrong.
Not really.
The settings file is named MusicBee3Settings.ini and it's in the AppData directory. If what you edited was in a directory named MB Settings Folder, then you edited a BACKUP of your settings.
Also, since each user's settings are more than likely different, the line numbers you referenced are not necessarily the same for every user.
Lastly, if it worked for you, great. But -you're- the one who saved/created the location of that file using File > Library > Backup Library.
EDIT: typo