Anyway, the main reason you'll see bit 3 being used is because it costs additional cycles to mask it out.
I see. I thought that the 3rd bit is set for reason because I failed to comprehend what's happening in the engine from the readPtn label and up to the playNote.
Haha, no, I can't take any credit for that discovery, you figured that out by yourself!
Thankies! Tho I won't be able to make it without the test track you've made ^~^