Coil Master kit Ohm reader off

[Dadaran]

Looks as though my coil master ohm reader has begun to be off by quite a bit a 0.22 reads as 0.3 Is this quite common?

Use a mod to check now, but prefer having something more cost effective to build on in case the juices flow with too much abandonment! Any obvious fixes or recommendations on better readers would be much appreciated.

Edit: not sure this is in the right sub forum