Dollar - Category N/A; Downgraded but no Discount Offered

On a recent (Nov 2008) rental with Dollar at DTW, my category of car was not available upon my arrival. I can live w/ that since rental cars don't impose the change fees, etc. that I'm so familiar with from the airlines.

However, I was disappointed that the Dollar agent -- upon offering me a lower category car -- did not offer me the corresponding lower rate.
Is this standard practice?

What did you book and what did they give you?

I don't know what official corporate policy is, but a discount is standard practice for this situation at the location I'm familiar with. It's usually only a few dollars per day or 10%, but that's all the difference between the car classes is online anyway.

OP Here.
Best as I can recall, booked full, got mid.
Eventually I requested a discount and got 10%. (which is fine, except that that was no offer for a discount until I asked)