Not wishing to be disrespectful to anyone.
Using pre-sprays as an example, we all use differing brands, with differing performance and in-use requirements and different dilution rates. So, product A) is a different price and dilution to product B)
The same goes for protectors. Some have higher active ingredient content, some also have top-up Stain-Resist dye-site blockers. Some are marketed in different ways too. So, dilution rates and prices can not be directly compared.
The mark up on protectors can be significant, so, IMO, your service should not be price led. My advice would be to find a product which you find easy to work with, which performs to the standard you are happy with and apply a price that works for you as well as the customer.
Safe and happy cleaning
Ken