Performed a web service in which customers can hire people for recreational purposes, at this time I have implemented the option of PayU to make the hiring, the case is that these people who are going to be hired charge for hours and each of these people has a different rate, on the page I have implemented a payment button which from the PayU page the price is set, the problem is that this price is fixed, so it does not matter if it is 1 hour or 10 hours the value the equal. I would like to know if there is any way to solve this problem