Since I have always used Manual settings for my flashes I have never thought much about TTL.

My thought process is if I use a single focus point on my subject and the meter uses the entire scene or portion (as set in metering),

Is there any compensation in the resulting flash power (duration) for distance to subject.

A focus point should be able to determine distance with at least some accuracy.

So if my subject is 5 feet or 15 feet or 25 feet away, realizing flash fall off, does the TTL factor this in?

Thank you