This behavior just cropped up a little while ago. Typically, in the past, when I ran into a problem with SPlat (or TTS-1) not recognizing a patch, it was because I forgot to set something somewhere. But when it reared its unwelcome head today, I quickly but thoroughly looked over the settings, and I couldn't spot anything amiss.
 
Specifically, I'm using TTS-1 and I have a tune with a total of six MIDI tracks (Melody piano, rhythm piano, guitar, bass, and drums, with a tiny 2-bar section of strings). Two tracks are suffering from this problem, track 1 (Channel 2) with the "EP Legend" patch (bank 03) assigned, and track 2 (Channel 4) with the "EP Phase" patch (bank 04) assigned. I've had no problems getting these patches to work in the past. But right now they're both playing the EPiano 1 patch, located on bank 0. I've rebooted SPlat once with no effect.
 
Sometimes I've found that SPlat will forget the patch that's assigned and if I reload it, SPlat wakes up a starts to play the correct patch, and everything's great once more. But that technique didn't work this time. I tried switching the tracks -- there are two of them, both piano, to different Channels than where they already were, and that didn't help. In one instance, it got a track stuck on Piano patch 1, grand piano, which was a far cry from one of the Rhodes sounds I was after. I had to exit SPlat entirely and then re to get that track unstuck from the grand piano.
 
I haven't tried rebooting the machine yet. I'll do that in just a minute, then come back here and edit this post.
 
UPDATE: Okay, it took me longer to get back to this than I thought it would. But here are some even more puzzling results. After rebooting my system, booting SPlat, and reloading the file, unfortunately it's still playing EPiano 1. So I tried switching banks to see if that would get things unstuck. Well, it did, sorta. When I shifted down to bank 01, it suddenly decided that an acoustic piano was called for. And when I shifted it back up to bank 03, percussion instruments sounded out. This continued as I shifted to more banks, then finally stopped and switched back to acoustic piano when I moved the setting down to a lower bank number. Now, back on bank 03, it's still stuck on an acoustic piano patch, when it should be EP Legend.
 
So, got any ideas where I should look?  Maybe reinstall SPlat?  Switch over permanently to CbB? By the way, I haven't tried this file in CbB yet. But why should I have to when everything else except this one file is behaving normally? I think.
 

Well, I have another update to this rather odd behavior. It gets even odder. I decided to give CbB a try, reasoning that this was a SPlat bug -- actually a TTS-1 bug, I guess -- that might have been addressed. Not sure if it was or not, but at least I got results. So I tried loading the same tune in the latest build of CbB. It initially played the same wrong patch sounds, while indicating those that I wanted, so I started changing some settings to see what, if anything, might make a difference. What I found was rather interesting. I was able to get Track 1 (Channel 2) to eventually produce the correct sound by changing the channel a couple of different times, eventually settling on Channel 1, which was open. So I tried the same thing with Track 2 (Channel 4). It wasn't as simple. It switched to acoustic piano when I moved to another channel, then percussion when I moved to another (that wasn't 10!), then I changed channels again, and next tried changing the bank, which didn't help, but I then tried changing the patches on the new channel and was able to finally get it to play the correct patch sound. The new channel ended up being 16. But while all this was going on, my bass track started acting up. It switched from TTS-1's slap bass 1 to something weird sounding, so I tried the same thing with it. Finally got it to "stabilize" on the slap bass patch after switching through patches and channels. Its original Channel had been 2. Now it's 15.
 
So what I'm most interested in now is I'm wondering, can anyone explain CbB's (and SPlat's) behavior? Why was it changing patch sounds when I was changing channels that were free and open? And why percussion effects when the channels weren't 10? But most of all, why did I have to jump through all these unnecessary hoops just to get the patches I'd selected to sound properly?

no patch/bank change events in the event list?

No, I checked it. Nothing but "notes". Strange, eh?

I cover this in my tutorial in the very first part, see my signature for link

If the project has gotten corrupted, you will be spinning your wheels trying to find the "cause".  Since there's no way to know at this point, best thing to do is start a new project and manually build up the project again, item by item.  It's the only way you're going to be able to pinpoint exactly what is going wrong. 
 
Did you import outside MIDI tracks?  If so, start there.  If not, go to one of the offending tracks and copy it to a new project -- what happens?  ... When you've completed recreating the project and it still misbehaves in the same way, then you've ruled out all the components and can then consider the application or the O.S.....

I explain this in my tutorial,, but any patch changes made with the GUI will be over ridden by the settings in the track inspector. You generally make all GM patch/ bank setting in the 2 locations shown above. 
If you wish to make the patch settings in the GUI menu then those boxes need to be set to "None" 
Check the event list for hidden PG events. 

JonD, I agree and this is a procedure I'll likely follow in the future. Currently, however, I've noticed this is an ongoing issue with a couple of other tunes I converted from BiaB format to MIDI just yesterday. Using CbB, I just tried the game of shuffling between channels and selecting different patches, then working back up to the patch I want. So far, this little game has continued to work.
 
Johnny, I don't usually make adjustments from the horizontal tracks the way you're showing. I prefer working from the Console View and I make my channel/bank/patch selections for the tracks in Console View. It seems to me, though, that it shouldn't matter where the changes are made from.

Yes the console view is the same as the track inspector so a good place to work too. 

mwmcbroom
...I prefer working from the Console View and I make my channel/bank/patch selections for the tracks in Console View. It seems to me, though, that it shouldn't matter where the changes are made from.

 
What happens if you select the same presets from the TTS-1 GUI itself instead of via Track View or Console View?