This stuff is normally used where RTD level accuracy isn't necessary. That said, I typically order the supplies in the special limits grade which specs to (in round numbers) +/-1C in the temperature range this would be. We have a calibrated thermocouple generator so I can validate pretty high accuracy in the instrumentation. What I don't have is a calibrated hot cell and cold cell, but usually I'll use an ice bath and boiling water as simple red-face checks for the complete system.
Bear in mind I'm not an Engineer, but my general function is to investigate and provide information so that we can decide if Engineering or other involvement is necessary.