Thanks for your response, dflat. I already did try writing out the first section without repeats, as you suggested, and that would work except for the fact that with one line for an Intro—at the top where it belongs

— and two lines for the closing endings, I needed 13 lines for this chart. Well, I actually did figure out how to make an iReal Pro chart with 13 lines and it works well, albeit a bit squashed. (See recent thread on that.) But it seemed that it would look better in 12 lines, and that it
should easily play with simple repeats in the first section.
I've been working with it all afternoon and it's turning out that the culprit really is the use of two 1st Ending signs. The second BC sections with their three endings work fine if you remove that first 1st Ending sign up in section A, but with both 1st Endings in there the final endings will not play correctly, even though it appears that they
should. (See Test 1, attached.) I also thought that it should work using Da Segno endings, but iReal Pro wouldn't play that at all, even though it seems to look right on the chart, too. (See Test 2, attached.)
The bottom line is: If you already have one repeated section,
with a 1st Ending sign in it, and you later make a second repeated section that has three endings, iReal Pro will not play the third ending properly.
If the first repeated section has just a forward repeat sign and a back repeat sign without a 1st Ending sign in between—no problem. It seems to be the existence of the 1st Ending sign itself that sets up the problem. (Even just tossing in an extraneous-debris 1st Ending sign that is doing nothing up in the first section will mess up the endings at the bottom.)
From a practical standpoint, this means that you cannot have a repeated section that has three endings if you earlier had a repeated section with two or more endings. (Like the chart I've been trying to arrange here.) This would not often be needed for just writing down a tune,
but it quite often will be needed for charting an arrangement for performance, particularly in jazz with its solo repeats. And my impression is that quite a few members are using iReal Pro that way.
Maybe admin and tech support will get a chance to look at this problem.
Thanks, again, dflat, for your quick response, even on the weekend. This is a great forum.
AABBB problem (2)
1. C'est Si Bon - Test 1 - Henri Betti Bb André Hornez (1947)
2. C'est Si Bon - Test 2 - Henri Betti Bb André Hornez (1947)