Hayo,
My plan, when I got a camera that populated the subsecond field, was to change the expression to this:
{dats}_{tmsl}
But, since I don't really care what values are in the subsecond field, I think I will continue to use my current expression since that expression should work with any camera no matter how it treats the subsecond field.
In other words, the expression I use now is pretty much camera agnostic!
Scott