The strange thing is that the bridge on my m75 is settled way more higher than your bit the action is really low… I got the opposite situation on the s100 so probably the production was not so consistent during 70sHi
I have a 74 M75CS and a 73 S90 and they both look to be about 12 at a very quick look. The S90 is in very poor condition needing lots of restoration so I cannot claim how accurate it is. It is missing bits.
I’ve attached a picture of the M75 for reference.
Did you luthier actually put a gauge on them and get a measure of the bridge and fretboard?