Track times not adding up (internal log)

[Kurt]

I've been using internal logging on the road course for data analysis, but my times aren't adding up with my videos.  I used a stopwatch while reviewing my videos to get lap times.  I use a switch on my steering wheel to trigger Switch #5 and add a custom marker for each trigger afterwards to get lap times in AEM Log.  I use a switch to turn logging on/off, have conditions for throttle, rpm, and vss all set to at least zero, and engine load to -13.10psi (lowest it will go). 

While looking at my log, I see no points where it stops and comes back, so it looks continuous.  Logging rate is 35.71 fast, 4.46 slow.

I gathered lap times from three sessions with both my videos and with the data log.  I used a stopwatch with lap memory, so I was able to time over 900 seconds of lap time continuously.  A Aiptek digital HD camcorder was used for video and I've tested it's recording speed with a video of my stopwatch, then played it back and all times matched up, so it's recording and playing back at real time.

First session:
total time from video: 652.77 seconds
total time from log: 626.38s
difference: 4.2131%

Second session:
video: 790.18s
log: 758.00s
diff: 4.2454%

Third session:
video: 962.84s
log: 923.86s
diff: 4.2193%

I've found that each individual lap is right around 4.22% quicker by my log data than the video time.  The slight % difference must be due to not hitting the stopwatch button quite at the right time.  It seems that I'm logging continuously, but it's at 96% real time.

Question I have is, can I change a setting and fix this??

Attached is one of the logs, if it helps.

Edit: Calculated % increase wrong, should be right now.

[Kurt]

Math was a little off, should be right now.  I find that, for any of my logs, if I multiply the AEMLog lap time by 1.0421925, I'll get the correct lap time.

[Kurt]

Did another test today.  Posted are two logs, one internal and one external.  Both were recorded over the same four minutes together (same input data).  Internal time for the four "laps" was 230.36 seconds.  External log added up to 240.00 seconds.  Must add 4.185% to the internal time to get to the actual elapsed time.  With a longer sample, it would surely have been closer to 4.21925%.

[Kurt]

Talked to tech support.  This is a hardware issue and can't be changed.    Oh well.