You're not really giving enough information for a truly specific and helpful response.
Where's the data coming from that is being "automatically converted"? Are you entering it? Is it being imported from an outside source?
Excel is doing what it's supposed to do, but the old computer adage applies: GIGO. Garbage in, garbage out. Somewhere along the line, the numbers in question are 100 times larger than they're supposed to be. It could be a format thing; more likely it's a data entry issue.
Is it possible for you to post a copy of the spreadsheet so we can get a look at the possibilities?