The refund advance ended on Feb. 15. Not sure what 20% discount you are asking about. The online fees that were in effect until February 28 were early discount fees. If you paid or filed by Feb. you got the discounted early fee. As of March 1 the online fees increased.
I filed in February but I didn't see the discount applied
We cannot see your account information so we do not know what you paid. The fees shown online before March 1 were the discounted fees---the increase for March was being shown at the time with a slash through it. For instance, in February Deluxe was priced at $39---on March 1 it went up to $59.
No one in the user forum can resolve a billing issue. If you have a question about your TurboTax fees or billing, make sure you use the word “billing” in your request for help. Do not use the word “refund.”
https://ttlc.intuit.com/questions/1899263-what-is-the-turbotax-phone-number
How do I look at the break down because I don’t see where it’s applied.
Did you choose to have TT fees deducted from your Federal refund? (Remember that if you did that, you also agreed to an extra refund processing fee of $39.99)
How can I see my TurboTax fees?
https://ttlc.intuit.com/questions/2565973-how-do-i-review-my-fees-in-turbotax-online