I am having the same problem with Finale 26 (as I did with 25). Whether the settings you choose 'stick' or not seems totally random. I know I can use the Finale Mixer (in the Windows pull down menu) to affect each channel volume, but I have changed the instruments on this staff to a channel that is higher than 16 - but ARIA player always changes the volume I set back to what it wants as soon as the space bar is hit. VERY frustrating.

UPDATE As an experiment I tried playing the piece back with a channel volume at 0 in the Finale Mixer and still heard 'forte' notes. I edited the "ppp" key velocity to 0 and marked the staves "ppp" and STILL heard forte notes. How are either of those possible?????

Yes, I get very faint playback sometimes - then I adjust the mixer to increase the levels, then all of a sudden, the levels come up and it BLASTS out. 

Just another one of the playback problems (I can make a long  list) that the company has never fixed.

I don't understand why setting the key velocity to 0 doesn't mute it. There is a major broken connection somewhere. . . . UPDATE The problem seems to be with Human Playback - as soon as select "none" the playback is correct. With any other preset "ppp" plays ball "f". So what's the use of Human Playback if you can't use it?

....and don't get me started on play back of bass drum rolls and marimba tremolos. Some days they work, and sometimes a complete no-go. 

Here's just a partial list of playback problems that the company has never fixed - but some are NEW ones that only have shown up when you pay$ for an upgrade!

1. Window sometimes does not flow with playback.

2. Several problems with the counter A. won't go back to start. B. Sometimes counter doesen't move forward or backward.

3. Weirdly, every new document I create stops playback at ms. 34!. I have to manually change this in every document I create! Finale just decided this all on it's own.

4. Yeah tremolos - good luck!

etc etc....