I believe the discount is up to $20. That is for the highest Self Employed version. So Premier is $15. You need to log in each time to Fidelity to get the discount.
How to get the partner discount
I looked up Fidelity....
Go to this page,
Then scroll down and Click on the Next Step - Get Turbo Tax now and save $20
Then You get to the Online versions
For Desktop, after you get to the page listing the Online versions go up to
Products and Pricing
Then pick CD/download Products