This is just my opinion...

Most of the time I think if the odometer jumps its reading, it has definitely been tampered. An odometer isnt exactly a very complex device. Just like a water meter. Even our 23 year old car has an odometer that had never jumped a digit. Of course it is entirely possible that there is a problem with the odometer, but this is highly unlikely.

Instead of just looking at the mileage, look at other indicators, how worn out is the steering wheel, seats, pedals, etc., Have the tires been replaced? How about the shocks? If yes, baka naman high mileage na yan na inayos lang. Sa pagkaka alam ko kasi shocks and tires would last more than the measly 30-40,000 kms.