Correcting a Variation in Temp using PID and RTD's?

[SAMPLER]

Currently running autotuning on my PID (SYL-2352) trying to get my heating element and RTD to set correctly. I have been getting temp reading on both RTD but the temps vary quite a bit from each other even if plugged into the same temp probe.

Also, I am getting a temp reading of 154 on a hand held thermometer but only getting 143/144 on the PID.

What steps should I be taking to correct this and make for more consistent readings?

Thank you for your input.

Cheers