YouTube - MegaSpin II - 14 Rotations
Is a video of a mate and I performing this exact kind of spin in an Aerobat.
Spin is entered with idle power but full back-yoke and inspin aileron.
As the spin is established we feed in some power, and it goes flatter. It feels out of control - you're literaly pushed sideways. To recover we reduce power back to idle and hold proper spin recovery inputs, but it takes a few turns to break out of the spin. You'll notice in the video that during the attempted recovery the spin rate seems to increase.
I'm not entirely sure why, but I wonder what the angle of attack is during a flat(ter) spin compared to a steeper nose-down spin...