Change oil light - ;05 Chevy TB LS

Owners manual states to change the oil when the oil light comes on. I am not convinced this is working, seems to flash ocassionally on startup then turn off after 20 seconds. If it were the oil change indicator, wouldn't it come on and STAY on? I HAVE reset it when I changed the oil. Just had the oil changed yesterday, the light was NOT on, and I don't think the garage reset the light. Can this light really be relied upon? Truck is driven mostly locally w/ ocassional long weekend trips, but seems like over 10k miles would go by without the light coming on.

 

I have 3 chevy trucks and yes you can trust the oil change light, don't mess with it once it has been reset , it is normal to flash at start up then it should go away, when time comes for an oil change light will stay on at all times until reset,use a good quality oil and a good filter and that's it.
Computer calculates life of oil based on engine operating temperature, engine load and other aspects and NOT solely on miles, this helps reduce harmful oil waste for the environment, 3k miles oil changes are a thing of the past , my work truck is a K3500 with the 6.6 L diesel and even pulling a trailer all the time it goes over 7K miles before asking for an oil change,wife's suburban goes for over 5K miles also...
These are modern engines , don't worry too much about it, just use recommended oil weight and a good brand
By the way read your owner's manual when light comes on oil should be changed within 600 miles ...