Due to some statistics used for artifact chances not being in the savefile, you will have to compare the "could find with" value with your ingame values for some artifacts. Currently this applies to the following: Power Orb, Beard Hair, First Crystal Fragment, First Iron Fragment, Second Iron Fragment, Third Iron Fragment, Excavated Mirage, Ancestral Hourglass, Lantern of Guidance, Vault, Battlefield, Blood Chalice.