Your best bet is to get a scanguage, torque app, or aerforce to actually read what the PCM is showing for temperature.
Every W-body I've had (five this year so far) would have a different spot on the gauge cluster for what "normal" was. Sometimes it was barely above 160. Other times it was smack on 210. My black car has a 160* and runs mid 160's... and the gauge is right on the first big line.