As I see it, there are two possible reasons that you're not hearing the sound.
1. Midi styles are automatically being replaced by Realstyles.
2. Your midi sound setup needs adjusting.
Does this help?
...
Yes it does! I went with your 2nd suggestion, and now it's all working beautifully, many thanks!
And if I understand things correctly, you're not a PG Music employee but rather a helpful volunteer on this site, correct? I'm simply overwhelmed with your helpful efforts, again thanks!