Looked to book some car rentals for the summer and realized that the rate through the Delta stays/cars website is giving me 10%-20% higher than booking directly with Hertz and using the normal Delta CDP.

Is Delta jacking up rates they are returning through that site to make up for the 'promo' ? I didn't see this issue with the last promo where rates matched what I saw through the Hertz or Avis site or through Expedia with the corresponding DL code.