You probably want to check things like memory usage and PLE over time, instead of making knee-jerk reactions to what you see on one particular day.  It may be that this particular system has more activity on a specific day of the week or month, so reducing VM memory now would leave the more intense processes short on resources.  A PLE that high typically means that it's been high for quite a while, the PLE starts at 0 when you first start the server, and will gradually increase until activity causes pages in memory to be removed so other pages can be read in (in a least recently used way) which will lower the PLE.