40 CFR §1027.125

1. (a)We will refund the total fee imposed under this part if you ask for a refund after failing to get a certificate for any reason.
2. (b)If your actual sales or the actual retail prices in a given year are less than you projected for calculating a reduced fee under § 1027.120, we will refund the appropriate portion of the fee. We will also refund a portion of the initial payment if it exceeds the final fee for the engines, vehicles, or equipment covered by the certificate application.
   1. (1)You are eligible for a partial refund related only to a certificate used for the sale of engines, vehicles, or equipment under that certificate in the United States.
   2. (2)Include all the following in your request for a partial refund of reduced fee payments:
      1. (i)State that you sold engines, vehicles, or equipment under the applicable certificate in the United States.
      2. (ii)Identify the number of engines, vehicles, or equipment you produced or imported under the certificate, and whether the engines, vehicles, or equipment have been sold.
      3. (iii)Identify the reduced fee that you paid under the applicable certificate.
      4. (iv)Identify the actual retail sales price for the engines, vehicles, or equipment produced or imported under the certificate.
      5. (v)Calculate the final value of the reduced fee using actual production figures and retail prices.
      6. (vi)Calculate the refund amount.
3. (c)We will approve your request to correct errors in the amount of the fee.
4. (d)All refunds must be applied for within six months after the end of the model year.
5. (e)Send refund and correction requests online at www.Pay.gov, or as specified in our guidance.
6. (f)You may request to have refund amounts applied to the amount due on another application for certification.