My old Elenco meter is giving voltage readings about 0.10v too high (at least at around 4 to 6 volts) and gives too high of current readings. Thread I posted about current here. I never fixed it. I just replaced it (although I find myself using it and forgetting the voltage readings are a little high). There are quite a few pots inside mine.
My XL-830L has proven good though with thick leads (I posted my test in the original T-Mart deal thread dchomak linked).
I'd suggest always trying to test your meter / leads with a Nanjg driver and fresh battery since you know what you should be reading.
-Garry