Services are based on weight. You sent 2lbs to Australia for 3000 pesos. I sent a 1oz letter to the US for 2000 pesos. That isn't exactly cheap. I told the guy at the ;post office I wanted the fastest service(?). If it were 3000 pesos for the letter I sent to get EMS service, that's not cheap at all. For another 600 pesos I could have sent it DHL, got 3 day service, and not had to drive all the way to POP.This is NOT EMS, you paid for cheaper and much slower service, which is not even fully traceable, that's why you only see when it was sent and when it was delivered but nothing in between.
EMS tracking numbers start with EE, your tracking number starts with RR.
It looks like there is an advantage on heavier packages, but not on letters.