The meters are based on a clone of the ICL7107 3.5 digit meter IC. This is a very common IC, and the documentation is very good. Look for Intersil or Maxim docs, they are almost identical. Also look for Intersil app note AN023. The short answer is yes, you can modify the meter to do auto-ranging. You will need some circuit to detect a voltage below 10 V (a comparator, preferably designed with a little hysteresis), and it will need to drive something like a relay to switch between two sets of resistors in the divider network that supplies the measured voltage to the 7107 inputs, so that the voltage is 10x higher when in the low range. You also need to switch the decimal point. The 7107 does not drive the decimal point, it is probably just hard wired on the board. Another modification you can do is to increase the measurement speed of the 7107, it can easily do 10 readings/second or more before issues start. If you do this, follow recommendations in the datasheet for sizing of the integrator capacitor, and use a good quality polypropylene cap, NOT a ceramic one.