I find that compared to residential jobs, a much lower percentage of commercial jobs will pay for a protector. In many circumstances I encouraged them to put the money toward more frequent cleaning program. That probably was better for their carpet than protector.
A lot of commercial carpet is olefin. Olefin benefits from the added protection against oil soils, but is intrinsically resistant to water-borne soils. No t as great a need for protector as in residential settings.
On industrial cleaning jobs that are cleaned on a regular schedule, Encapuclean with Maxim provides some protection and it will build up over several cleanings. So they get protection, you get easier to clean carpets without the additional cost of a protector or extra labor. Charge 2 or 3 cents per sq. ft. extra if they want this level of protection.
For the industrial jobs where you do sell protector, you can cover more square feet with the same amount of protector if it is low pile CDG style. You can probably make out OK for 8 to 10 cents per square foot added to the cleaning cost.