MH conversion for the last two weeks of flowering

I have read in a back issue of west coast cannabis, a coloum by Ed Rosenthal that had the mention of using HPS(obviously) for massive flower growth, due to its replication of the sun. He then specifically directs the grower to use MH for Veg, HPS to begin and do all but the final two weeks of flowering. He then suggests that returning to the use of MH for the last two weeks of the bloom phase will *significantly increase the THC production, with something relating to the wider spectrum of the bulb as well as its higher UV output.

I was wondering A.if and how true this is?....
and B.who/how many people are using this technique and how efficient is it. would there be a better method or is this by far quite effective?

thanks.:20