triple000:what do i need 2 get my av.down 2 from it's present level .
With your saturated average, you won't get a -2 on your average - you'll become promoted before, at 63 ;)
In general, it depends :)
Unsaturated, you'd need what a simple average calculation needs: A few very good scores or a lot of fairly good scores, all minimum 2 below the first average, i.e. < 63.
Saturated after 40 Master rounds, it depends on the scores values in the pool. You may experience high drops in the beginning, when a 70 expels an 80 (10/40 = -0.25 though the 70 is above the average). Later, it becomes more difficult.
But, don't care too much! Have fun in the game and shoot the lights out - you're gonna advance for sure!