Unit of quantity in excise return and sales invoice

you have to follow any one unit of measure under excise 

if you have opted CuMeter then you excise invoice will be CuMeter basis only, 

though you are set free to make comercial invoice in your choice, 

but you have to make ready the co-relation chart between CuMeter and Kgs, 

as Kgs can not be Cu Meters and vice versa Cu Meters can not be Kgs 

The stock records should be maintained such that both the measurements are covered - the conversion factor should be standard and verifiable from technical books. The list of records required to be disclosed should contain the fact that the quantities are different and how they have been co related.