Bluetrew, asking about "normal" with PCa is unwise. There is so much variation between individuals in their response to chemo. Your oncologist is on the ball, having reduced the dosage, because of the toxicity. Your OH may have gone as far as he can with docetaxel. It may be that the lower dosage will work better for him. The sort of variations you have reported don't seem unusual to me. The chemo has worked, the question is, will it continue to work on the lower dosage? Only time will tell. Meantime it is providing a measure of control. Stick with it and trust your oncologist.
Good luck.
AC