Update line 32 from:
$Shipping_Packaging = 0;
to:
$Shipping_Packaging = 1;
Update line 58 from:
$Shipping_PackageArray[$Shipping_PackageIndex]["Quantity"] = "".WA_eCart_FormatNumber($jackitsCart->DisplayInfo('Quantity'), true, 1) ."";
to:
$Shipping_PackageArray[$Shipping_PackageIndex]["Quantity"] = "1";
That should make it treat everything as one package.