The actual wording of the requirement is:
(e) During the recovery part of the maneuver, it must be possible to prevent more than 15° of roll or yaw by the normal use of controls
So, if I can control the plane within that, I'm okay with it. If it's 20 degrees, and I have good control, I'm still okay with it. If it bites, and I feel that the control I have is not confident, even 15 degrees could seem questionable.