Two things: if you weren't measuring the output voltage under load, then you weren't measuring anything terribly useful. Second: LED's are typically constant c

Two things: if you weren't measuring the output voltage under load, then you weren't measuring anything terribly useful. Second: LED's are typically constant current devices. If they don't receive a _minimum_ voltage, they just won't light up at all, but if they do, and the current is regulated properly, then the exact voltage doesn't matter (or rather, is a function of the LED's demand, not the supply).