I got my DS0203 a few days ago with hardware revision 2.72.
I have performed the calibration for zero offset and gain many times, but the oscilloscope always show wrong DC voltages (about 2V off in 10V mode).
I use this tutorial for calibration:
For calibrating the zero offset I connect CH_A to ground and the offsets seem to be measured correctly. But after successful calibration (and selecting ‘exit and save…’) there is no Y-position that is close to zero (see pics). In the pictures shown below I manually adjusted the Y-value trying to get the DC voltage near to zero (but without success).