You want to simulate the growing of your score so you need variables
score = points in my example (It keeps the actual score, than you add 1 to it every X seconds)
newPoints = a variable to help you let the score growing, it just saves how much you need to add over time to the players score.
For your first problem:
-> Do you try to make achievements ? If yes trigger once is the false condition.
If yes you need a small achievement system, with an array or something else.
If you want I can explain it you a bit more.
Sry for the bad english, need some coffee :D