For ASME Y14.5M-1982, ASME Y14.5M-1994 and ASME Y14.5-2009
When using inch units there will be no leading zeros and the decimal places for the feature of size, distance dimension and tolerance must match.
When using SI (metric) units, like mm there will be a leading zero but not a trailing zero and matching the decimal places between dimension and tolerance is NOT required.
We'll do our best to get you the aright answers here and in my GD&T training classes!I cant really find information on this on the internet.
Chapter 2 of the ASME 14.5-2009 and my book "Geometric Boundaries II" defines the syntax for expressing dimensions and tolerances for both metric and inch units.
Also, ISO 2768 units are given in mm therefore no trailing zero's or matching decimal places and leading zeros required when applicable.
Don't ya love it!