placo1
You could run the same test, at the same station again every 5 minutes, with different results.
Idle speed, plus minus 25 - 40 rpm has no meaning.
HC's are caused by many things, such as ignition, overly rich mixture, overly lean mixture ( to the point where you'd have misfire ), a degrading catalytic converter, a lazy O2 sensor, slight amount of oil consumption. You want me to keep going?
My advice to you: You passed the test, don't worry - be happy !
It runs well ( starting, power, fuel enonomy ), LEAVE IT ALONE.