That is a common misconception about the Level 4 with XL upgrade. The Level 4 and XL are 2 completely different motors. The XL upgrade consist of the XL coil and 1 extra spider. This does not make it an XL, it just makes it an upgraded Level 4.
Also it is no longer know as the Level 5 upgrade. The XL and Level 5s used to use the same coils. Now that the Level 5 is a 3.5" coiled sub, it is known as the XL upgrade.