Hi
@Alex Ng - Apptio should not remove precision via the upload process. It may appear this way in the user interface though (please see article below). You may also confirm that Apptio has kept the precision by exporting the table and selecting "Unformatted with precision of 15 decimal places". Apptio uses the more precise number in calculations but displays only 3 decimal places unless something is specifically formatted to display more.
https://community.apptio.com/viewdocument/how-to-why-is-numeric-data-limited?CommunityKey=425255f0-2344-4925-89f0-f0eced22345e&tab=librarydocuments
#CostingStandard(CT-Foundation)