Data type causing mismatch between Excel and Matlab

I have defined a matlab function (see below) with some inputs and outputs. Outputs are a result of some equations with in the matlab function. There is one such equation that computes values very close to 1.0 and because of the data type issue, i am not able to match the excel results to matlab results. I prototyped the model in Excel already and after satisfactory results, i started building up the model in matlab for a more wider analysis of data. Here is the code:

function [A, B, C, D, E,F,G,H] = Control(Rawdata, a, b, c, Constant1)

D = Rawdata/(constant*a);

if(D>=1)
    value=1;
else
    value=0;
end

As I mentioned earlier, D ranges between 0.978 to 1.004. My model is based on this D value equal to or greater than 1.0. Matlab's output has more 1s than excel and I guess number precision is the cause. Can someone help me figure this out.

Thanks a lot.

[Geoff Hayes]

Rama - does the Excel implementation have a similar function that computes D as above? If so, what can you say about the Rawdata, constant, and a variables that both MATLAB and EXCEL use? Are they identical, similar or ..? It must be one of these three variables that is causing the difference between the two applications.