Number of Signature Spells?

[Spiteful]

I have a 3rd level sorcerer in my game who just got his signature spell feature (CRB page 193) but I am not sure how this will work as he continues to gain levels. Will he keep adding another signature spell each time he gets access to a new level of spells or does he just get the two signature spells for the rest of the game.

[HammerJack]

One for each spell level.

[Ravingdork]

So 10 potentially, depending on how high a level the character progresses to.