What are your ambient room temperatures?

As vivi said, make sure the thermostat probe for the UTH is sandwiches between the heat mat and the bottom of the tank on the outside of your enclosure.

For the CHE, hopefully someone who uses those will chime in with probe placement suggestions.

Part of the issue may be that it sounds like you are actually measuring ambient air temps as opposed to surface temps. To measure surface temps you'll want to purchase a temp gun. You can get them for about $15 on Amazon and can probably find one at home improvement stores.

What kind of thermometer are you using to measure your air temps? Is it digital or the stick on kind you find at pet stores? The stick on kind are wildly inaccurate. You want a digital thermometer to measure air temps. A popular one are the Acurite kind, about $8-$10 at most Walmarts.