Updated July 26th, 2016
This article describes the WPM browser caching behavior.
WPM 2.2.1 and earlier
By design there is no data cached between playbacks.
It is not possible to set the WPM Player to cache entries, if the transaction had some information cached, this would affect the page load time calculations and there would be unexplained variances when the cache expires or between fresh connections when there is no cache.