I beg to differ, Icon. It's not neccessary to score below the average but to boil down the scores included.
In TWTs score pool for the average there are scores probably from 60 to 66 (seeing only the last 200 entries). Any score up to 65 replacing an existing high number (up to 66), should drop the average, much more the two -5 31s on STA he scored in the last two days (=62 for average calculus).
Another example, I'm at 63.03 (=63.025 exactly), and I know that a single 64 will make me Tour Master though it's above the average (there's a 65 to eliminate) :)
@TWT: I can't believe that the number should not have dropped - perhaps an old, not refreshed number in the main window might have fooled you?