When I use GoSurf50 for my phone, I only needed to have 50 pesos as load. When I bought and started using Globe Prepaid Home WiFi modem, it always require me to load it with 55 pesos instead of just 50 pesos. I cannot subscribe to GoSurf50 if I load just 50 pesos. It's a hidden charge I don't want. Why is this so?