Don't want to wee on your cornflakes, and I don't know what Facom digital calipers cost, but if your Mitutoyo digital calipers were surprisingly (or rather, suspiciously) inexpensive then there's a decent chance you have a counterfeit set.
About a year ago my Mitutoyo Digimatic cost about £130 from digitalmicrometers.co.uk, who are reputable resellers.
Clough42 did a video on the fakes: