更新PayPal的定期付款配置文件中的每笔金额？

Question

For example I have four different amount($40, $30, $20 and $10) for my product. I create a recurring profile with first amount. Now my second amount is different from first. So how can i update automatically my second amount for running recurring payment profile in PayPal. I used UpdateRecurringPaymentsProfile method. but for this we required manual running php file. Anyone can help me.