Suppose I have an Italian SIM and pay x to call Italian numbers, and 2x to call French ones. If I go to France, with these rules, I think I'll still pay x to call Italian numbers, and 2x to call French ones?
No Symbiote, his assumption is correct. You will pay 2x for calling french numbers, but still x for calling italian numbers. I also tried these days (my operator activated this regulation last week). I went to Italy with the german card and I could call german numbers for free(that's in my contract) but I was spending more to call italian ones (2 cent btw).