Try pressing CTRL-SHIFT-PgUp a few times to add delay to any frame-swap the game might be doing. I'm not 100% certain if it will work for this game.
I'll have to check the boot script for this game as I don't recall if it self-regulates or needs slowing. You might have come across a bug in ADFFS as I'm sure this used to run at the correct frame rate when run via Boot Floppy.
EDIT: I've checked the boot script and my notes. The script doesn't slow the game down as it self-regulates. I've tried it on a SA and it did run at the correct speed, so I'm unsure why it's running fast on your machine. CTRL-SHIFT-PgUp won't unfortunately slow this game down.