Question Customisable hardware monitor

I'm trying to use Open Hardware Monitor with an old Gigabyte GA-945GCM-S2L motherboard. Unfortunately it displays certain voltages incorrectly. For example, the +12V rail is reported as 3.072V, which suggests that there is a 3:1 potential divider at the input to the multi-IO chip (in fact it is 24K : 8.2K). Also the tool is reporting a bogus value for the +5V supply (it is not actually sensed by the motherboard).

Is there a way to customise the calibration factors for the various voltages? I was able to do this in the past with Motherboard Monitor (great tool, but no longer updated). Otherwise, is there an alternative free tool which is customisable in this way?

Gigabyte motherboard schematics (GA-945GCM-S2L):
https://elektrotanya.com/gigabyte_945gcm-s2l_rev_1.02_sch.pdf/download.html#dl (pages 6 & 26 show monitored voltages)

Code:
VIN0 = Vcore  x1
VIN1 = DDR18V  x1
VIN2 = VCC3 (+3.3V)  x1
VIN3 = PWOK  x1
VIN4 = +12V (24K : 8.2K)  x3.927
VIN5 = VID7  x1
VIN6 = VID6  x1
VIN7 = VCC (5V)  x1  (4.080V, always overranging)

BIOS displays Vcore, DDR18V, +3.3V, +12V.

BTW, Open HW Monitor has a config file (in XML format) which appears to contain calibration factors, but these appear to be encoded in some kind of ASCII format (base64?). I'm really not looking forward to wading through the program's source code …