My friend suggested going back to the last day I loaded my mayor and playing a little...plant some trees, move flowers, put down some patterns. I've done it a couple times and both times it gave me different plots when I went back to plot resetting. (It hadn't given me any options remotely close to what I was trying for so I was worried.) Worth a shot?
Also, Have you seen this link to make sure he is able to plot where you want him to?
http://www.belltreeforums.com/showthread.php?310996-The-precision-of-villager-plot-resetting