Surface RT: Less Standby Battery after Dec2012 updates?

Maybe this is just me, but is anyone else noticing substantially less standby battery life after the RT's most recent updates? Usually I have about 85% battery left after getting home from work with light usage for maybe half an hour total during the day. It seems that lately I'm down to about 65% with that same usage. I know that the most recent update played with Wifi settings, so maybe that has something to do with it. My company does not have Wifi in the office, so it's not even connected to a hotspot though.