formula should return zero, but gives 0.05 as percentage

Hello all.

I'm trying to put together a nice little invoice template for myself to be able to use for any job I work on.

I seem to be having a problem with one of the calcualtions that I am performing. Please take a look at it;

=IF(PRODUCT(E40,0.05)>0,PRODUCT(E40,0.05),"")

This is in a line below a SubTotal line (E40) to calculate a 5% tax on all items. When there is nothing in the SubTotal, this should show a zero......but it's showing 0.05. How do I make it show a zero instead? Is it just something simple like the formatting on the cell?

Thanks for the help on this!

Cheers!