Nikon p510 Auto focus at tepe photo end

I can't say I find that to be true..I have taken video and zoomed in or out slightly and it focused properly, although with a slight hunting effect sometimes.. I also have had it NOT focus properly.. I can't say when it does or does not, but I have MANY very good videos taken with the P510 at full zoom...I always use a tripod to keep the camera as still as possible..Most pros use a tripod to keep their long lenses steady, and I think it's a good policy..I know I can't hold a 1000mm lens still..Jimmymac