If you wait 3 minutes after riding for 1/2 hour,and shutting it down, to check your oil ,is that the same as starting the bike ,running it for 3 minutes,shutting it down, then checking your oil?

I would think any amount of running the engine prior to taking an oil reading would have the same effect. You need to wait for all the oil to drain back down to the pain. Get off, take your gear off, stretch, stare at the sweet mustang that just drove by, then check the oil.