The Current Time Indicator never arrives on the last frame of the composition.
If the composition has 560 frames, CTI only get to the frame 559.
This is correct behavior because the CTI always shows you the start time of the next frame to play and the comp panel displaus that frame. If you moved the CTI to 560 you would be looking at the start time of frame 561.
That is how all video and audio apps work. Always have.