As not everyone fully understands the scoring system. It works approximately like this.

Progression:
0-100% average progress meter
OR
0-25% progress contribution by each survivor/player.

Health
Health Bonus 0-200 total points OR 50 points per player.

How the health bonus is calculated:
Regular health / 2 = Health bonus for each survivor +
Temporary health / 4 = Health bonus for each survivor

Example:
If you have 40 temporary(bleeding out)(and no medkit) health then you will contribute 10 points to the health bonus score
If you have 80 regular health(medkit'd) you will contribute 40 points to the health bonus score
if you have 20 regular health and 20 temporary health(and no medkit) then you will contribute 15 points to health bonus. (20/2+20/4 = 15)

The medkits and pills are automatically calculated into the person who is holding them. As if you were to use them before end.
You can gain additional points by healing someone without a medkit if you have a much higher health bonus then them.
example:
1 player has 100 regular life and medkit = 50 health bonus
2nd player with 10 regular life and no medkit = 5 health bonus
Total score = 55 health bonus
1st player heals 2nd player with medkit (thus causing 2nd player to go to 80 regular life)
Total score = 90 Health bonus


Survivor Bonus Multiplier:
0x, 1x, 2x, 3x, 4x
There is no difference between 0x and 1x, The 0x is assumed to be 1x in the calculation.

Map Multiplier:
1x, 1.3x, 1.4x, 1.5x, 2x for each level of the 5 levels.

Calculation:
(Progress meter + Health bonus) * Survivor bonus * Map multiplier

Maximum score for each 5 levels
Level 1: (100+200)*4*1.0 = 1200
Level 2: (100+200)*4*1.3 = 1560
Level 3: (100+200)*4*1.4 = 1680
Level 4: (100+200)*4*1.5 = 1800
Level 5: (100+200)*4*2.0 = 2400
Total maximum score for a single game = 8640