The Vs figure quoted in the POH is at MAUW.
Depends on the POH performance section. The better documents will have more data and schedule the speeds/distances according to the weight.
Interestingly, if the approach speed is solely for MLW, the landing distance required usually then increases with decreasing weight, largely due to the increased float .. but it saves dollars in the work up side of things for the OEM or subsequent modifier.
Small bugbear of mine, I'm afraid ..