Fix two bugs with Marathon A3 grading

S4 now correctly has 3 internal grades instead of 4
You can get a green-line GM

tetris/modes/marathon_a3.lua

@@ -309,7 +309,7 @@ local mroll_points = {10, 20, 30, 100}
 local grade_conversion = {
 	[0] = 0,
 	1, 2, 3, 4, 5, 5, 6, 6, 7, 7,
-	7, 8, 8, 8, 9, 9, 9, 10, 11, 12, 12,
+	7, 8, 8, 8, 9, 9, 9, 10, 11, 12,
 	12, 12, 13, 13, 14, 14, 15, 15, 16, 16,
 	17
 }
@@ -354,8 +354,7 @@ function MarathonA3Game:getAggregateGrade()
 	return math.min(
 		self.section_cool_grade +
 		math.floor(self.roll_points / 100) +
-		grade_conversion[self.grade],
-		self.roll_frames > 3238 and 32 or 31
+		grade_conversion[self.grade]
 	)
 end