Why are Kybella and Aqualyx administered differently for submental fat?

I’ve researched Kybella and Aqualyx and they appear to have a similar mechanism of action and indications for submental fat. However Kybella is administered by a grid like pattern with many small injections while aqualyx is done through a single injection while moving the needle around depositing the medication. Is there any reason for this? Why cannot aqualyx he administered like Kybella and visa versa? Aside from that FDA approval of Kybella and not aqualyx of course.