Hi,
This option excludes the website-specific taxes, unfortunately there’s no easy way to predict the payment service fees (I recommend setting the commission rate enough to cover these). This option is useful if you charge extra taxes like VAT and don’t want to include its amount in the vendor balance calculations.
Taxes can be set up in WooCommerce settings Setting up Taxes in WooCommerce - WooCommerce
This depends on the country and the required taxes, e.g. some marketplaces pay VAT on behalf of the sellers, if you want sellers to pay VAT for themselves then it should be included in their balance.