Fix for PMPro Proration Add On, Japanese Yen, and Stripe (make sure level costs are integers)

my_pmpro_checkout_level_fix_prices_for_stripe.php

<?php

/**
 * Fix for PMPro Proration Add On, Japanese Yen, and Stripe
 */
function my_pmpro_checkout_level( $level ) {
    // Make sure level costs are always integers.
    $level->initial_payment = intval( $level->initial_payment );
    $level->billing_amount = intval( $level->billing_amount );
    return $level;
}
add_filter( 'pmpro_checkout_level', 'my_pmpro_checkout_level', 20 );