Your math is correct, and your reasoning is also correct,that it doesn't realy matter.

however the answer is not 100% clear

from what i understand.......... mach will go to the nearest step without going over 410.1= 410, 410.2= 410, 410.3=410, 410.4= 410

410.5=410, 410.6=410, 410.7=410, 410.8=410, 410.9=410, 410.912432=410.

so my understanding is correct mach rounds down to the nearest whole decimal?

? without going over?

my machine has an accuracy of .0024375....

i understand that it is not a cumulative problem as all measurements are from home!!!!!!!!!!!!!!!!!!!!!!!

the question is DOES MACH ROUND UP OR DOWN!

I am sorry if i am hashing this over like crazy, but........ I am more interested in the answer, than if it really matters...

Hood, I did the math you posted... it is good.... and probly cant even measure it....... and doesn't matter, the fact it carries out to 16 digits there is only one choice .0023475 plus or minus when it hits the magical 410.500000000000000000