Incorrect Mailing Address for Exemption Processing of Healthcare.gov

The mailing address for Exemption Processing on Healthcare.gov is:
Health Insurance Marketplace
Attn: Exemption Processing
465 Industrial Blvd.
London, KY 40741

However, when I tried to send an exemption application (on behalf of a family member) in the post office via Priority Mail, the clerk told me that the zip code for "465 Industrial Blvd., London, KY" is 40750, and I must change the zip code to 40750 in order to get it delivered.

Therefore, I called Healthcare.gov to ask which zip code to use, a supervisor told me that 40750 is for handling supporting documents; the Exemption Processing uses a separate zip code (40741) because it could be a different physical location.

Since the zip code, 40741, is rejected by the post office, could anyone share some insight on which zip code I should use for Exemption Processing?