HPS vs MH

Ok, so I know that for vegg you would use MH (6.5k temp), and I know that HPS is for Flowering. (2.7k temp).

The thing that I am confused on is that I have seen some grows using HPS Through out the grow.

So my question is, can HPS be used through out the entire grow?
(I am assuming that it can, but you wouldn't get a very bushy plant. Correct me if thats incorrect.)

You can use whichever one you want whenever you want, its just a matter of ideal conditions to maximize production.

I personally only us MH setups. I use a 3000k MH bulb works great. I sometimes use a 20 dollar 400 watt Lowes 4000k bulb which also works fine.
Good luck