Quantity Digits to Accompany Level Modifier Code
00 - Level 1
01 - Level 2
02 - Level 3
03 - Level 4
04 - Level 5
05 - Level 6
06 - Level 7
07 - Level 8
08 - Level 9
09 - Level 10
0A - Level 11
0B - Level 12
0C - Level 13
0D - Level 14
0E - Level 15
0F - Level 16
10 - Level 17
11 - Level 18
12 - Level 19
13 - Level 20
14 - Level 21
15 - Level 22
16 - Level 23
17 - Level 24
18 - Level 25
19 - Level 26
1A - Level 27
1B - Level 28
1C - Level 29
1D - Level 30
1E - Level 31
1F - Level 32
20 - Level 33
21 - Level 34
22 - Level 35
23 - Credits

Note 1:
With this code, it at least the first two missions. Causes FMV glitches. Leave off until in the city. Further testing reveals that this code does not work on disc 2. A new code will be posted when available.