Mars pro 2 epistar 320 - flowering time, also supplementary light

I have a Mars pro 2 epistar 320 in my 4x4 tent.

For those who don't know:
Advertised at 1600w
Actual wattage pulled is 750w.

I got 2 things on my mind:
First, my flowering time is a full 20 days longer than my buddy, who runs a 600w HPS. I'm hydro, he's soil. He even got clones from me, so same genetics. Why? My red diesel was a full 74 days from 12h switch, his is 54. This has proven consistent with other strains as well. Isn't led usually a faster flower? Especially in hydro?

Second, the footprint of my mars 2 is really only 3x3. What is my best upgrade to get a better 4x4 footprint? Add an extra light, or ditch the led and get...what? I'm really looking at the cmh, but a 315 on its own is a 3x3 footprint. A full 4x4 footprint is my priority.

What does RIU day?

Are you running the same temperatures as your pal? With that light you probably need to be even a couple degrees warmer to get the leaf temps up. I wanted to get full wall to wall coverage and ended up building my own light using Samsung strips for the base light on one driver and adding what amounts to the Rapid LED Mass Medical supplemental kit broken up into three different drivers so I have total control of the spectrum.