Do you mean prochem dry compound cleaner Gary? I'd imagine it will do a respectable enough sort of job for that type cleaning.
If you've got any m-power or nemesis that type of product is good as a little bit of extra boost applied before the dry compound, but you have to be careful if the material is prone to water marking. If it's got stains on already you should be able to see if it is water marked or lost colour from the previous attempts to clean it by the customer

Mix up a bit of the product in a trigger sprayer that makes a fine mist but NO DRIPS. Mist it over from a good 3-4 feet above the carpet, several stairs at a time and brush it in, then go over as normal with the dry compound. Use a soft bristled hand brush to work it in. Most importantly it needs to be properly dry before final vacuuming. If it isn't dry it will clog your vac up and stay stuck in the carpet (tbh there will always be some left in the carpet). Problem with this stuff is if you put an air mover on it you'll create a dust storm in the house! I normally use a dustpan & brush to get up the thick of it, then try to put a fan on it so it doesn't start blowing round everywhere.
Charge a lot more money than HWE, it's a time consuming pain in the a$$ job!