Logan Graham

You can remove the hook that WC uses like so:

remove_action( 'woocommerce_add_to_cart', [ WC()->cart, 'calculate_totals' ], 20 );

However, if you have any sort of ‘mini cart’ that’s being displayed in the header, sidebar, etc, then that will likely call the same function before it’s output to make sure the end user is getting the most up-to-date calculation / rates. Otherwise, the user will experience a minor delay while visiting the cart page as it will have to retrieve those rates so they can be shown to the user. I would still advise testing that thoroughly to make sure it works with your system / setup.

If your WooCommerce installation is up to date, they’ve actually become quite good about caching returned rates and only recalculating that – via the calculate_totals cart function – when the cart or address has changed. Unless there’s a rogue plugin or addon that’s causing it to run that function on every page WC itself shouldn’t be requesting those updated totals.

As far as fixing it on every AJAX load, the code snippet and instructions I put above should resolve that atleast for the R+L plugin. You would have to see what is calling the UPS update separately – whether that plugin specifically or whatever might be running calculate_totals.