There are different units of measure in 3dsMax: centimetres, metres, foots, standard units, etc. Modelers might prepare a model in “their own” units and later, when exporting, there may appear discrepancy… Units of measure are stipulated beforehand, but in practice it often all comes to “I forgot”, “There are the right ones, aren’t they?”, “Everything was set correctly, that’s Max’s mistake!”.
In 3dsMax script you can have a value in system units from currents units of measure, using the function decodeValue
For example, f = units.decodeValue( 1.0 as string )
Reserse conversion is realized using the function units.formatValue <value>
You should take unto consideration the global value of scale a use sets
scale = units.SystemScale