Which dry density to use?Density of cement or MDD of subbase materials

[defg]

I have got some arguments between my colleques.We are dealing with stabilization works for C1-stabilised subbase.After analyzing the laboratory trial tests revealed that 3%of cement is adequate. Now on my case I want to make field trial test of 100m length and my road is 9.8m wide and the thickness of the stabilized subbase is to be 200mm.
I carryout the following arithmetic in order to know how much tonnes of cement I'm going to use in this 100m length.
Volume of soil =100x9.8x0.20=196cum
Weight of soil=196x1910kg/cum=374.36tonnes (1910kg/cum is MDD of the subbase material)
Cement used on site=3%x374.360=11.23tons.
Our main argument here is that my colleagues are using density of cement instead density of subbase material! Who is correct? As the density of cement is do high compared to MDD of subbase material!!3120kg/cum>1910kg/cum this makes the Contractor to use more cement than required! But the Consultant claim that this is appropriate way to use the density of cement!!!Please assist

 

[BigH]

I have never heard of using the density of cement before in this matter before. Sounds like the blind trying to lead the sighted.
You have done your lab tests, I presume, on the percent of cement based on the weights of the base material. That means you use this same mix formula in the construction.