No prob. I think that if you add the 150w hps it may make the resin glands become much more active and may make your plants reach out more to that light... might not be a bad idea but I am planning on only using cfl and 60w halogen bulbs on my grow.

I really like these outcomes of let wattage but just the perfect amount of light to give you some of the best buds around.

Honestly your plants looks beautiful and seems that you have a perfect setup so I would just continue what you are doing and not change it untill you need to.

Sorry just stoned off some Lemon OG Kush