They overfilled it!

Last week I took my '04 in for its 6-month oil change (4,200 miles). These folks seemed to really know what they're doing, but they over-filled the oil by about 1/4 inch. Today I took it back in and they happily drained the excess, leaving it a tad below the full mark.

I never checked the oil during those first 6 months, because I'm not the kind of guy to go messing under the hood, and because I trusted them, and assumed it came filled to the proper level from the factory. Now I'm wondering if maybe my mileage would have been affected by that 1/4 inch of extra oil, or if there's been any damage to the engine (though I doubt that a small over-fill would actually damage a Toyota engine.)

I understand that a large excess can cause the oil to foam. But does a small excess actually do any damage? Wouldn't they build in a bit of leeway, putting the FULL mark a bit below the damage point?

 

So maybe it really doesn't matter at all, and all this talk about never overfill it!!! max-full mark is somewhere more than 1/4 inch above the mark on the dipstick.