When I use BIB (and gear select), and set the gems to epic, rare, unknown, etc., Mr. Robot chooses the correct gems for my spec (in this case haste for a feral druid with correct Wowhead item numbers), but list the stat values as much higher than the gems actually are:
Quick Golden Beryl at + 30 Haste, when its actual value is currently +7 Haste.
These high numbers are then being used in the stat calculations (verified by deleting the gems).