Those flashing dots are SP points, not EX points.
There’s a japanese website that fully explains the grade judge system along with lots of other stuff. I’ll edit with the URL later tonight.
The “EX” section of the grade judge is determined as follows.
-How many consecutive rounds have you won so far? (CPU game only)
-How did you win each round? Normal/special/super/time/chip/etc.
-How varied were your attacks? This is determined by tallying the number of times you did each possible attack and looking at the highest number. The lower the number, the better.
-Will this grade be an improvement over your last one? In a CPU game this will show as an SP point in your final stats, but the bonus exists in a two-player game too.