You might have noticed it from your own memCron graphs, if not, check the demo out. I believe DreamHost is rolling out a new update that gives extra swap memory to your PS server. This is the reason why you see the jump right after memCron changes your memory setting, signifying more memory is available than what memCron expects.
While memCron might act a little weird because of this change, the good news is if this change is permanent, memCron can operate at a lower margin, and you will be able to save even more money with it! I will update memCron to adapt to the new memory settings as soon as the memory change is confirmed by DreamHost. I might even release a quick fix at the mean time, once I find the time to do it.
BTW, I also notice you can now create a root user for your PS via DreamHost panel.