Looks about right Dan. At 55cents for cleaning, that's 27 1/2cents for protecting when charging half the cleaning price. I lower the price when cleaning t/a's, so 1/2 of that price still works out nicely since I'm not applying it to as large an area.
If you're only charging 20cents to clean, the protector will add significantly to your profit margin. Plus, its not cheap so don't just give it away.
I've been using the Maxim. Applied it to my own carpets and it was still beading spilled liquids in a high traffic area after a year. I cleaned and protected my carpets every year, so the best term to use is "Reapply/Reinforce protectant" as it always is applied at the factory, and if you applied it the year before, it hasn't all worn away.