Or is that is what it is suppose to do - max Tv was set to 10 seconds but camera went up to 13 seconds is that ok?
As I mentioned, it's an old script. Most likely the code I used to covert seconds to APEX96 units is "off by one" in the lookup table. If I feel energetic at some point, I'll take a look. The handling of AV96 values on camera's without an aperture might benefit from some study too.
If my interval was 16second, what is the max exposure in seconds can I get away with?
Allow yourself a little less than three seconds per shot for focus, set exposure, shoot, save image to SD card stuff. So I would not suggest setting the TV low limit below the 10 seconds value you were using if you want to shoot every 16 seconds.
