Page History
...
When using the option of a customer's return to the shop, it is recommended to sent an additional request about the authorization result to IPS Assist server after receiving data about the paid order at URL_RETURN_OK (for information about the authorization result request refer to section 3.3see details) in order to make sure the order payments have been performed. It is recommended as well to send an additional request about the authorization result to IPS Assist server after receiving data about the paid order at URL_RETURN and URL_RETURN_NO, because a customer is redirected to these addresses with different payment state, including the state "In process".
...