Here is the formula for Plus Points:
Plus = (bomber kills x 2.0)+(other e/a kills x 1.0)+(assists x 0.25)+(targets destroyed x 0.10 to 0.50)+(AI GVs destroyed x 0.25-0.50)+(AI A/C destroyed x 0.5)+(AI ships sunk x 2.0-3.0)
Bombers do not include JU52 or Dh98IV, or similar aircraft, C47. These are counted under other e/a kills. AI ships are 2 to 3 points depending upon size and are worth more in Carrier Events. The other variable scores depend upon the type of series, GV's destroyed are worth more in Tactical Series.
Here is the formula for Minus Points:
Minus= [(DWD + MIA)x0.25]+[(ditch+capture)x0.5]+[bailx1.0]+[KIAx2.0]
This is fairly straight forward.
To qualify for a medal in a series, you need positive points and not have a KIA and must have attended 4 or more frames.
A Lady Luck can be used once per CUP (3 series) to remove a KIA.
This means that if you had a good series, but were Killed in Action once,you could use the Lady Luck to remove the KIA and regain the 2.0 points that a KIA costs.