Many years ago the developer of SIDBrowser was good enough to implement the following feature for me. I hope I can convince you too!
The SID Tai-Pan by Peter Clarke has a fantastic SubTune 2 that only goes for 50 seconds but when you played the game it looped indefinitely. So it wasn't supposed to be heard just once. To be fully appreciated it needs to be looped a few times.
The composer designed the SID to loop seamlessly. Now you could make it play again & again a few times in a playlist but when you shuffle the playlist it won't work. It's not just about hearing more of that music, it needs to be heard all at once.
Can you please make an option to repeat SubTunes in a Playlist?