Hmm, this is a display formatting issue (the zeros are added when you convert the decimal to a string).
You need to see where in code you are seeing the trailing zeros. Is it after a call to .ToString()? Try playing around with the different formatting strings:
.ToString("#");
.ToString("0.00");
.ToString("#.##");
And so on. The best way to do this is just to experiment with the different possible values.