Re: Problem student!!
It sounds to me like the alleged "problem student' is pointing out that the OP is over powering his techniques unecessarily. PS is proactively taking ukemi because he is anticipating damage.
I think there could be some compromise from both aggrieved parties. The OP could lighten up a litte or a lot. PS could let his partner know in advance how much power and force he can manage. I agree with the previous post that practice should be cooperative and that they need better communication.
Work it out between yourselves and try to get along, 'k? That is a good part of what Aikido is about.