Fix PayPal Rounding Issues. Add to theme functions.php file

gistfile1.php

add_filter( 'woocommerce_paypal_args', 'fix_paypal_rounding_errors', 10, 2 );

function fix_paypal_rounding_errors ( $paypal_args = NULL, $order = NULL ) {

	if( $paypal_args ) {

		foreach( $paypal_args as $key => $value ) {

			if( substr( $key, 0, 7 ) == 'amount_' || substr( $key, 0 , 9 ) == 'shipping_' ) {
				$paypal_args[$key] = number_format( round($value,2), 2, '.', '' );
			}

		}

	}

	return $paypal_args;

}