custom buyCRED exchange rate

/**
 * Adjust buyCRED Cost
 * @version 1.0
 */
add_filter( 'mycred_buycred_get_cost', 'mycred_pro_adjust_buycred_cost', 10, 3 );
function mycred_pro_adjust_buycred_cost( $cost, $amount, $type ) {

    // Get our custom exchange rate (defaults to 1)
    $rate = get_option( 'buycred_exchange_rate', 1 );

    // Calculate cost based on the amount the user selected to purchase
    // Note that most payment gateways (not all) requires the cost to be
    // formated using two decimal places.
    $cost = number_format( ( $amount * $rate ), 2, '.', '' );

    return $cost;

}

/**
 * Setup Cron
 * @version 1.0
 */
add_action( 'init', 'mycred_pro_buycred_rate_cron' );
function mycred_pro_buycred_rate_cron() {

    if ( ! wp_next_scheduled( 'buycred_custom_rate' ) )
        wp_schedule_event( time(), 'hourly', 'buycred_custom_rate' );

    add_action( 'buycred_custom_rate', 'mycred_pro_change_rate_cron_task' );

}

/**
 * The Cron Task
 * @version 1.0
 */
function mycred_pro_change_rate_cron_task() {

    // Get current reate
    $rate = get_option( 'buycred_exchange_rate', 1 );

    // Update your rate in any way or form

    // Save new rate
    update_option( 'buycred_exchange_rate', $rate );

}