Markup-by-Attribute changes the product variation prices on the back-end when you use the Set regular price
or Set sale price
bulk edit functions. It sets the price of the individual variations, rather than adjusting the price on the product web page. This approach may not work the way you need it to.
Usage instructions can be found here; Markup by Attribute for WooCommerce – Installation. Scroll down to USING MARKUP BY ATTRIBUTE FOR WOOCOMMERCE.