The "rating pool" is different so you would expect there to be some differences.
I'm pretty bad at blitz and I mostly use my time on tactics. For me, my tactics rating is much closer to my online/daily/correspondence rating. But the main thing is that in a TT situation, I know there is something there but in a live game, I may not be able to see available tactics quickly enough or if I do see them and get an advantage, may not be able to finish the game in time or will end up blundering under time pressure.
I have seen so many people with tactics rating much higher than their playing rating. I do not believe I am terrible at tactics, but my tactics rating is pretty much in line with my blitz rating.
Am I missing someting about solving tactics that I should be aware of, which could help me improve my tactics calculations? Or is it just that most people on this sight are great at doing tactics?