Look I know nothing about the ammo in question, and little about subsonic ammo in general. Luckily for you I'm a member of this board, which as we all know, is even better than staying at a Holiday Inn Express.

The two things I can say for certain is that subsonic ammo will deliver less foot pounds down range than the equivilent standard ammo simply because the bullet is moving slower.
The flip side is that this might not matter at across the living room distance, and you will have less of a worry about going through the neighbor's wall.
I'd shoot some, see if it cycles, and if it does I'd use it for the bedside gun.
FQ13