I believe USDOL is for worker's comp, which I have zero personal experience with. When I did dabble in workers comp (almost 20 years ago), there were some unique rules to workers comp that did not follow standard coding guidelines.
1) What is the reason for the denial?
2) For information about 99417 from AMA
https://www.ama-assn.org/system/files/2019-06/cpt-office-prolonged-svs-code-changes.pdf
3) For information about G2212 from Medicare
https://www.cms.gov/files/document/r10505cp.pdf
Rule #1 for prolonged services is that you must already be billing the highest level. You cannot bill prolonged with anything other than level 5. The time thresholds for 99417 and G2212 differ. The codes are not interchangeable based solely on the carrier.
Just because a code exists does not mean it is covered by a carrier.
Hope some of that helps, and perhaps someone with WC knowledge can also assist.