Fix shipping calculation in plugin

On our Wordpress site you need to correct the calculation of the cost of delivery in the plugin "courier-shipping-for-moscow".
Detailed TK here: https://docs.google.com/document/d/1X7VkwZ1hO2cEzPqDyFFoFzxP3c0RtrDuhk0iPGnF3eA/edit?usp=sharing

P.S. When responding, please indicate your experience in PHP, Woocommerce, as well as cost and timing.