But any repairs paid for by the owner can be and often are excluded from reports. Anytime I pay cash for bodywork I all that nothing get entered. They always do as I ask. I don't want a couple of $500 - $1000 minor repairs on my vehicle body over a few years to effect it's resale value. So my vehicles always have pristine clean records.
That's why I LOL at folks who think that a Carfax is legally required. It's not, it never was. It's a third party tracking company that makes money on people who put way more faith into it than is deserved.
It can be 100% accurate or it can be totally inaccurate. You can also get the VIN from a car in the mall parking lot this afternoon, enter that into the Carfax phone application and enter fake repairs/maintenance of any sort. You can falsely log synthetic oil changes performed every 500 miles that were done at the dealership spanning the life of the vehicle. It must be true, it's on the Carfax
If I get your VIN I can list the repairs for the head on collision performed at a local body shop, and the new salvage yard engine.... And the replacement ECM/TCM/BCM/FCM because your vehicle was in a flood. And it's all true. Just as mine is all true because it says nothing.