HPS vs. MH in vegg? Have I learned something?

I've been at this growing gig for 20+ years and have always gone with the conventional wisdom to use MH for vegg and either add or solely use HPS for flower.

I recently had the opportunity to grow a very large garden for a dispensary in The Springs. 90,000 watts. Fun!

The point/question is this: All they are using is 600 watt HPS from start to finish and I'll be damned if the plants didn't seem to do MUCH better in vegg under the HPS! The node length was shorter, leaves greener, stems sturdier, and bud formation was splendid. WTF? I had some personal strains there and they reacted the same way using my personal dirt.

Any one else find MH unneeded?

IF they are using a newer hybrid type HPS they give better results than the older type of HPS bulbs. There are some articles out their that i have read on this subject that things have changed and for older people like us conventional wisdom has become outdated with all the new advances in bulbs.