Incomplete carfax?

[dbgrate]

I'm trying to check out a '91 420SEL ad in local paper.Ad says,125K mi..The last mileage shown in the carfax is @85K,that was in 2006.The last listing is a Benz dealer inventory(late in 2008),but doesn't show mileage!I assume it was a trade-in...but what do I make of the @40K over close to a 3 year period,early 2006 to late 2008)?? Any thoughts? Thanks!