Although I now only use Host Dry Extraction as a problem solver, I used it quite extensively in the past for both residential and commercial work. The system is capable of superb results, but it can be very time and labour intensive. I found the biggest drawback with the system was the spotting. Whereas with wet and LM cleaning, many spots come out without any extra work, Dry Extraction requires most spots to be treated individually. Although I've never tried it, I suspect that a pre-clean treatment with a microsplitter may reduce this factor. I've achieved superb results on oily/greasy soil and Host is still my system of choice with toner spillages.
As for charges on the example given by KL, I would charge a premium for the added benefit of a totally dry carpet on completion, probably about £150, but consumables are high cost. If you have a USP (unique selling point) such as this, it demands a premium. At £60 for Host, you will not be in business too long.
Good fortune.
Safe and happy cleaning

Ken