2004 TAHOE Z71 ENGINE OIL CAPACITY

I have had trouble getting a decent answer as to why my 5.3L V8 Tahoe will not take 6 quarts of oil as the manual says.  Has anyone else had this question or problem??  When I change the oil, I always drain the oil first, then with the drain plug still out, I remove the filter and let the residual oil drain thoroughly before replacing both new filter and plug. However, 6 quarts always seems to be too much - the dipstick shows a level about one dipstick hole higher than it should (the dipstick has four holes to indicate one quart I believe).  The manual says not to overfill with oil or some engine damage might (emphasize might) occur.  Is this really a problem or am I concerned about nothing? Hope someone has had the same observation and can explain.  Thanks  

Do you check the oil before or after you've started the engine?
 
I would not hold the capacity mentioned in the manual as exact. The last 1/3 to 1/2 quart of oil should be added gradually until the dip stick indicates the appropriate level.

I think mary900's  advice is the best,  but I also think if you put the full 6 in I don't belive you will have any issues. over filling is putting in more then 6 quarts or adding oil when the engin is not cooled off some and the oil has not had time to drain back into the pan to give a correct reading on the dip stick.