mileage tampering on gen3 prius?

I'm in the middle of a purchase of a used 2010 Prius. There was some oddities in the vehicle report from autocheck: a year and a half after purchase it says 60,000 miles on the registration, a few months later it's reported again as 30,000. The lady that owns it will be looking for service records but at this point there's no proof which mileage is correct. Her story is that she misreported the miles to the DMV when transferring registration from her father.

The story does seem plausible, but can the odometer have been somehow hacked/tampered with? Currently there's 50,000miles on the car. Assuming rollback that should be closer to 80,000. I'll be seeing the car on Wednesday, would there be any interior/exterior/driving notes that I should keep in mind which may help me see whether she's telling the truth or not? Would a mechanic familiar w/ Priuses have tools that'd allow you to see whether there's been some hackjob modifications done to the internal chips?

 

Thanks John, that sounds like the best way to look something up assuming it was serviced at the dealership. This is being sold by a lady that doesn't care about the car to the point of rounding mileage readings to the 5th digit(!), it does seem difficult to believe she was involved in any foul play... but these days you really can't tell. Hopefully she's at least been changing the oil every 5-10,000 miles.

 

I got the car. She had all records, everything looked straight. Car looked immaculate on the inside, outside it looked like she had the cheapest possible car carrier bring the thing over using vice grips on the bottoms of the cars (or at least you'd think it w/ the scratches there). Runs like a champ, honestly could care less if the thing was more banged up than it already was since I'll keep it till it's dead or totaled. Now to figure out how to cover up the worst offending blemishes...