Flex watt problem or Herpstat problem?

My herpstat was set at 93.5*, and my acurites were reading 90* inside the tubs. Tonight I noticed that almost all of my snakes were hanging out at the front of their tubs, which is unusual for most of them. I checked the acurites and they were all over the place, from 88* - 101*. I double checked with a temp gun, directly on top of the flexwatt, and it was reading 98*-112*. I took moved a acurite probe and placed it directly on top of the flexwatt, outside of the tub, and it read 98. I then dropped the herpstat temp to 87*, and the acurite directly on top of the flexwatt is now reading 95*.
So, is the flex watt or herpstat messing up?
Should I try moving the herpstat probe somewhere else?

where is the acurite probe and herpstat probe placed? Lets just say you have 5 tub rack. You want to put the herpstat probe in the middle of your rack system. If you put the probe on the bottom of the rack, the top will be a lot hotter because more energy is being used to maintain that certain temperature at because the bottom is colder, but at the same time the top is getting hotter.

Where exactly is the herpstat probe? it is very common that flexwatt has temperature variation edge to edge and from the end to end. What is the power output on the herpstat reading % wise it may be the probe if it is under has pulled free or is being effected by something else. Do you have aluminum tape on the probe? This can cause false readings. The last thing is are all the accurites reading the exact same if placed in close contact? I have never found them to be very accurate and probes can easily be damaged. The way digital thermometers work is to measure micro changes in resistance, if the wire is damages at all it can change this by a large degree. (I have one that had a door closed on it hard and it changed by 18ºF)

Id try it on another rack if you have one. Thats a large variation in temps on the flexwatt. Mine only varies ~4F in any rack.

It sound like the herpstat probe is off the flex watt, it happened to mine a few weeks ago and thank god i went back into the room because my snakes would have cooked overnight.

Oh what is the ambient room temps? My rack is in a cool room (below 68ºF always) and I get 10º top to bottom if I don't make adjustments for the room temp. I never though that could be contributing too. It is also possible that a couple of issues could contribute to the issue as well. I would contact Dion (spyder robotics) and see what he thinks he can help diagnose the issue.