I got the impression AK_in_OR was referring to your updated evaluation (10 for the second tourney + 20 for the third + 30 for the fourth, etc). Computing this type of sequence is simple in a programming language, but not so easy in a simple formula. There's no built-in function to do this for you, but one could be added. In the meantime, you'd have to compute it using pre-determined values. I'd do it like this:
sum(scores) + (switch(count(scores) - 1, 1, 1, 2, 3, 3, 6, 4, 10, 5, 15, 6, 21, 7, 28, 8, 36, 9, 45, 10, 55, 11, 66, 12, 78, 13, 91, 14, 105, 15, 120) * 10)
That allows for up to 15 tournaments played. Any more and you'll have to add additional values to the switch() function.