Average speeds aren't a good indicator unless you use the same route on roughly the same conditions and compare the rides.
If I'm practicing TT drills I typically choose a flat route, or flattish, and use my gps device to record the 'lap' as the tt event and compare the time/speed/etc to past training events to gauge improvement.
Same with hills climb training, intervals, etc.
They are different and the speeds are all going to be different.