Interesting. Thanks for the chart thing.
Yes the pause timing is a bit weird but it is dependent on how fast the engine loops, which as you stated might differ on various machines.
In regards to the time it takes to display the animation, I think most people probably won't even notice if it plays a little fast or slow. The only person that really knows how fast it should play is you or the animator that created said animation. So a couple milliseconds or seconds here & there shouldn't really matter...
The important thing is getting the timings of interactions right. The best approach for that is by adding action parts directly into the animation frames themselves, that way you can trigger when to change a condition, update a value, start another animation playing, trigger some dialog or whatever.
I think you will end up losing all your hair (if you haven't already done so) if you spend too much time worrying about things like timing. Sort your game first then worry about it later on. Besides I couldn't really tell you if any other engines would get timings perfectly spot on either. The only things I can think of are gif animations & rendered videos.
P.S: Try to remember that it's a game & not an animated movie, so things don't have to look über smooth.
P.P.S: I like how you misspelled length
on your chart but correct in the text you wrote above the attachment.