Taxes

In WooCommerce, you must set the taxes before running the import if you select Tax inclusive.

Duh.
Of course I had set the taxes in WC before import.
I have a standard tx rate of 21%

standard setting: https://i1196.photobucket.com/albums/aa409/Petertje101/standard_zpsfo31n2t2.png

low setting: https://i1196.photobucket.com/albums/aa409/Petertje101/low_zps1pu4mif8.png

reduced setting: https://i1196.photobucket.com/albums/aa409/Petertje101/reduced_zpsd9zqcttt.png

Import settings: https://i1196.photobucket.com/albums/aa409/Petertje101/importsettings_zpsccdo4cnk.png