Here's my take on it
The first four digits before the underscore indicate the card number and the final two digits after the underscore indicate the clip number.
Depending on the length of the number after the underscore, the first 1, 2 or 3 digits represent the type of clip, and whether the clip fades out/cuts or whether the girl enters and/or exits, and the presence of props.
The number between those initial digits and the clip number indicates the level of nudity.
In the following post, there are a number of examples to illustrate, where the relevant number is replaced by "D", non-relevant numbers are replaced by "#", and using the following key tp represent various attributes of the card.
S = standard full view dance or strip (not close up)
C = close up, where girls appears to be sitting on, or standing behind or in front of the task bar.
P = Pole Dance
U = fade / cut
E = Entrance / Exit
N = non-nude
T = Topless
F = Full Nude
X = Explicit
Q = props other than pole used