11.6V does not strike me as all that out of line, it's low by less than 5%. I don't have a schematic of the boost converter to look at, but usually regulation is accomplished by monitoring the output of a voltage divider made of a pair of resistors between the output and ground. The regulator compares the output of the divider with an internal reference voltage and varies the duty cycle accordingly. If the resistor values are a bit off, the output will be off as well.

I think your problem is elsewhere. Even if the 12V were way low, the machine should still operate to some extent.