After plant stops growing in Flowering, is an MH light needed?

Have a quick question hopefully someone can help me with.
Since I started growing years and years ago I always went with a single 400W Light.
Now I'm using a 2 light setup and I was told 400W Of MH & 400W of HPS is best for flowering if I'm using two lights and only 1 plant.

Now the question is, after the plant has stopped growing (Week 3 of flowering at the moment, no more signs of stretching) Is having 2 400W Hps lights better than 1 MH 1 HPS?
Thanks in advance.

You'll get better quality from the halide, but a bigger yield from the HPS. I'd do a mix and get the best of both worlds.

Sounds good, thanks for the advice, and the quick reply.
I'll keep a mixed spectrum as it isn't hurting me any.

I love a mixed spectrum and so do my plants, I also rotate the plants so ....3 days under the mh 3 days under hps. but sometimes ive noticed certian strains will make airy loose buds if mh is anywhere close to them?? sativa domate mh is probably good for them, indica dom. probably likes the hps since the suns natural color changes in august and sept.

MH simulates summer(vegg) time when the sun is high in the sky. HPS simulates fall(flower) time when the sun is lower in the horizon. It makes them stretch more witch is what you want. Makes more room for buds.