M ( ms ) vs. M ( md )

A discussion begins here, I'll let you decide the answer ;): Hornresp

GM

I was hoping you would chime in : )
I remembered to see Futtrup
( I think you turned me on to his page years ago)
DPC Manual

Mvac=M(md)

* Mair, Dd

Mair := rho/3*power(Dd,3);

or (when measuring),

Mair := 8/3*rho*power(Sd/PI,1.5);

* Mvac, Mair, Mms

Mvac := Mms - Mair;