I do exactly the same so that I can play the instant the file loads.

Intro cannot be saved in panel memory, because otherwise if you call up a panel memory with intro in the middle of the song you will be in trouble because it will be recognised as ending.

Syncro is stored in panel memory so you can stop the backing, and start playing backing again just be selecting a panel memory.

The solution is to make sure intro is on when you save. Then the file will load with intro on if you do the rest of the things you describe in your post, ie save current panel too.