400 W HPS and 400 W MH combined?

Hello guys. I never grow with HID lights before and now I managed to get some space
about 1.5 x 1 meters (5 x 3 feet). I did veg phase with 400 W MH only and it is time to put them to flower. I have 400 W HPS for that. Would it be wrong for any reason if I keep both lights on?
Thanks.

Hell no there would be no problem. If you don't mind the extra power consumption you will get great result with 800 watts of HPS/MH combo. In fact thats what I will be running next week.

Yea if you don't mind the power usage do it.