Max Situps in 2 minutes = if you score 100 situps in 2 minutes you subtract 100 points       (920 - 100 = 820)

Max Pullups = if you score 20 pullups you get 20 points x 6 = 120 points subtract from   (820 - 120 = 700)

Another option if you are really needing to cut hairs with selection programs is to add in body weight as a PT exercise
(so subtract bodyweight).

The added in bodyweight will give extra points to a 200lb person who can get 20 pullups compared to a 150 lb person who can get 20 pullups.  It makes the playing field even on effort / exertion.  These tests tend to favor the smaller candidate who can typically run faster and do more bodyweight calisthenics, but it does not penalize you for weighing less.  The goal at selection is to have a fair playing field for each candidate.

Now the scoring method for the above example:

700 - 200 lbs (points) = 500 total points for a 200 lb student taking this test.

700 - 150lb (points) = 550 total points for a 150 lb student taking this test

Then setting up scoring criteria is easy, but completely subjective by the graders to want you create for your test.  The thing this test will do is rank them numerically for the assessment team.

For instance:

less than 500 - Outstanding
501-550 - Above Average
551-800 - Average - passing
801-900 - Below average - minimum standard
greater than 901 - failing

This test is just an example to demonstrate an idea for scoring criteria.  Obstacle courses, shooting skills, and other job related events could and should be tested and graded on a different scale.

Adding in bodyweight and subtracting from cardio scores insures that testing can be scored fairly when competing for a slot in a Spec Ops unit.  Say a 200 lbs guy get 10 pullups and a 150 lb guy gets 10 pullups – the 200 lbs guy gets 260 points - the 150 guy gets 210.  Remember, multiply pull-ups by SIX (x6) for the fitness test to give it as much weight as 1-2 minutes of pushups and situps.  This gives the pullup test an actual exertion assessment pound for pound.
 
We used to do this type of scoring trying to figure out who went to SEAL Training from the Naval Academy and found it helpful when selecting only 15 candidates for training out of 50 excellent candidates.  Of course, the interview, resume, grades, and other factors were considered, but having a numerical value next to their physical tests gave us a ranking system to use to assess physical potential to make it through the training.