Customize the payment plan cost text on the level 2 checkout page

my_pmpropp_custom_plan_cost_text.php

<?php
/**
 * Customize the payment plan cost text on the level 2 checkout page.
 *
 * You can add this recipe to your site by creating a custom plugin
 * or using the Code Snippets plugin available for free in the WordPress repository.
 * Read this companion article for step-by-step directions on either method.
 * https://www.paidmembershipspro.com/create-a-plugin-for-pmpro-customizations/
 */
function my_pmpropp_custom_plan_cost_text( $plan_name_raw, $plan ) {

	// Bail if not a level 2 checkout.
	$checkout_level = pmpro_getLevelAtCheckout();
	if ( empty( $checkout_level->id ) || 2 !== (int) $checkout_level->id ) {
		return $plan_name_raw;
	}

	// Customize the plan cost text based on the plan name.
	switch ( $plan->name ) {
		case 'Annual':
			$plan_name_raw = 'Annual Payment – £600 plus any applicable sales tax';
			break;
		case 'Associate Membership':
			$plan_name_raw = 'Monthly Payment – £60 plus any applicable sales tax (£720 per year)';
			break;
	}

	return $plan_name_raw;
}
add_filter( 'pmpropp_plan_cost_text_checkout', 'my_pmpropp_custom_plan_cost_text', 10, 2 );