Hello my name isXXXXX will be assisting you with this problem today. Thanks for trusting us to help you with this appliance question.
That is absolutely not true, The oven should read plus or minus a few degrees not 50. The problem here is the oven temp sensor, The control board reads the resistance in the sensor not the temp so it's very easy for them to go out of calibration. The tech will need to test the oven sensor with a ohm meter, If this does not read around 1080 ohms at room temp. If it is not on or close to this mark then it will need to be replaced.
If the sensor reads correct then the control board is out of calibration and may need to be replaced.
I would request a new tech with the warranty company, obviously this guy you had is not appearance.
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