The issue is with the currency conversion thing you are doing and how you are calculating the grand total based on the taxable total from the cart. This doesn't includethe shipping or handling. Since your cart includes a shipping charge, that is what is causing the problem.
If you don't want to convert the shipping charge you would have to still add it to the grand total on line 77 like this:
$grandtotal += $eCart1->GetShipping();
If you do want to include the shipping in the conversion then you would have to use the Grand Total from the cart and do the same conversion on the shipping field below.