Round to weight and dimensions nearest upper integer if destination country is Switzerland. Work with WooCommerce FedEx plugin https://www.xadapter.com/product/woocommerce-fedex-shipping-plugin-with-print-label/

function.php

add_filter('wf_fedex_request', 'remove_fraction_for_switz', 10, 2);
function remove_fraction_for_switz($request, $order) {
    if ($request['RequestedShipment']['Shipper']['Address']['CountryCode'] == 'CH') {
        $request['RequestedShipment']['TotalWeight']['Value'] = ceil($request['RequestedShipment']['TotalWeight']['Value']);
        foreach ($request['RequestedShipment']['RequestedPackageLineItems'] as $key => &$value) {
            if( isset( $value['Dimensions'] ) ){
                $value['Dimensions']['Length'] = ceil( $value['Dimensions']['Length'] );
                $value['Dimensions']['Width'] = ceil( $value['Dimensions']['Width'] );
                $value['Dimensions']['Height'] = ceil( $value['Dimensions']['Height'] );
                $value['Weight']['Value'] = ceil( $value['Weight']['Value'] );
            }
        }
    }
    return $request;
}