Yes, the rounding mentioned by Mathias is a Pathfinder Society rule to allow balanced play between multiple players, GMs, sessions, and locations. It makes it easier for everyone to know exactly how many hit points a PC should have.
The standard rule for non-Pathfinder Society PCs (i.e. at home games) is max at 1st level, then roll the hit points normally, generating a random amount each level. However, there is table variation between standard, max hit points, Pathfinder Society average (mentioned above), reroll any "1", minimum half, etc., because how a particular GM want to run this type of game.
If you're the GM for a home game running with your friends, do what you feel is best. If you're not sure, using the Pathfinder Society standard is a good starting place. You can always change it later.
