Extech ph110 temperature accuracy?

[vertlook]

Hi,
I got this highly rated Extech ph110 and noticed that it takes a very long time for it to adjust temperature (something like 5 minutes for 10F) and even after that it's temperature measurement is highly inaccurate. I am comparing to my calibrated Maverick ET-7 and at 86F the Extech would show ~78-80F. Now, since it is adjusting PH value according to the temperature, shall it be a concern? I checked PH/temperature table and see that 10F difference equals to about 0.02PH drop. What is your experience with this meter? The documentation does not mention any calibration procedure.
Thanks!