Well not to split hairs "BUT" 1 cm =.3937". 1 mm =.03937". Rounding mm's to four decimal places will give .0394". My convert program shows 1 mm carried to 8 decimal places as .03936996. Rounding to 5 places gives us .03937, not .03934.
Here is my original statement on this, as you can see I did use mm's not cm's which was actually the error I was correcting & to which you have followed suit;
I believe you have your decimal point one place off. 1 mm = .03937" (1/25.4) or approximately .040". Thus .1 mm = .004" while .01 mm = .0004" or a bit less than ˝ thousandths.
