Fix tax rounding problems in WooCommerce

wc_round_tax_total.php

WooCommerce stores tax subtotals rounded with the same number of decimals that are set for the store, which can cause problems when invoicing on external services

Example when using 2 decimals and tax 23%:
Total itens (without tax): 68.24
Itens tax (rounded with 2 decimals): 15.6952 = 15.70
Shipping (without tax): 4.73
Shipping tax (rounded with 2 decimals): 1.0879 = 1.09
Total taxes: 16.79
Total: 72.97 + 16.79 = 89.76

How most ERPs would calculate taxes:
Itens tax: 15.6952
Shipping tax: 1.0879
Total taxes (rounded with 2 decimals, at the end): 16.7831 = 16.78
Total: 72.97 + 16.79 = 89.75

To avoid this, we can use the 'wc_round_tax_total' filter to force taxes to be stored and calculated without rounding

<?php

add_filter( 'wc_round_tax_total', 'fix_wc_round_tax_total', 10, 4 );
function fix_wc_round_tax_total( $rounded_tax, $value, $precision, $WC_TAX_ROUNDING_MODE ) {
	return( $value );
}