When I check the battery when not loaded it is higher than when loaded. For example, I am currently vaping on a Phoenix Bottom Coil. When I take it off, the battery check reads it has 3.6 volts. When I place it back on it reads it has 3.5 volts. After I take a hit, it reads it has 3.4 volts left. This seems to happen even w/ Boge 3.0 cartomizers and a tank. It also occurs with all of my batteries and different types (AW IMR 18490 and 18350). Just wanted to know if this is common, or if I should be worried.