The phrase "upward revision" means making changes or adjustments that increase or raise something, such as a number, a forecast, or an estimate. Full definition
The result was a fairly significant upward revision in the seasonally adjusted employment totals since 2011. (empirecenter.org)
But it is the first time we have seen upward revisions for quite a while. (rba.gov.au)
-LSB-...] from scraping over rocks, can melt ice at the base, a factor that's forced upward revisions of the rate of ice loss from global warming. (climatestate.com)