If I switch my light in the last week?

I was wondering if anyone knew if I were to switch my hps to a mh in my final (flush) week if more THC will be produced in that last week.

I would just add a small mh light but alas I don't have space for additions.

If you have the ability to use both types of lamps in a flower room, by all means, do so and your yield will increase. The reason most of us don't is because of space and heat issues. I'm not so sure going to a blue spectrum ONLY in the last week is a good idea, as it'll send the plant the wrong message.