weakness

When I play a game I am weak like 1100 or 1200 but my positional and tactics training scores are like 1700 or 1800. Why is the difference so big? Is there a calibration problem, or is there some other reason?

If your performance is volatile and ability varies greatly than how you play towards tactical / positional chess, that may be a hint that you need more experience and practicing to master controlling material.

#1 You might have a point (that the ratings aren't the same). My classical rating is 2027 and my Training rating is 2282.

Do the ratings need to be the same?

no they do not need to be the same, but i think the source of the problem here is the limited number of tactics problems. when i first worked with the trainer here, it was about three hours before i started to see the same problems appearing, over and over again. you are most likely remembering the solution, which is not a bad thing.

also, seeing a line from a given position is something i find easier than getting someone else to go along with attaining that position from move 1.

the more i think about this, i have had this problem as well, if you can see complicated tactical lines, but not beat 1200 rated players, my problem was giving enough respect to the mind playing the other side, tactics training is good, but there is nothing on the other side trying to beat you there, in blitz, my losses were dominated by not accurately assessing my opponents threats as being faster than mine. in the tactics trainer, you start from a complete dominant position typically.

#6 Agreed, Training puzzles won't help you play consistently - they'll only help you to learn to spot opportunities in positions where you already recognize that there's an opportunity.

You know how to solve the puzzles, but you don't know how to reach the positions in the game where there is something to do like in the puzzle?