How do I calibrate a Venom Pro Charger? HELP!!

[Savage-Flux]

umm, I just finished charging the pack again, lemme go check......... charger reads 4.19, 4.19, 4.20, whish apparently is 12.60, and same readings with the other chargers, look at the time of this post, and look at the time of my earlier post, its been charging since then......... I will chack multi-meter voltages tommorrow, considering my dad is asleep at his own house. oh and BTW, one battery finished before the other one.