bigmac,
One... since you don't know the source, I'm sorry but your example is totally pointless.
Who knows how that test (if it even existed as you wrote it) was set up?

I'm sure I would have picked the system that was set closer to correct over the one you said was set wrong on purpose if asked which had the more balanced/solid surround field.

This doesn't prove that the SPL meter calibration method was more accurate than by ear. This test has nothing to do with debating that issue. The test (as you described it) is only showing that a level matched system is important to a surround set up.

I totally agree with this.

Personally I use a 4.1 system w/ Newform Research speakers in phantom center mode (not that I recommend this set up for everyone, but more speakers doesn't simply mean better).
This creates an inherently perfectly matching center in both tone and volume to my mains. Panning is inherently perfectly seamless also in my system, and with my rear Newforms ~110 degrees behind dead center the surroundfield level matched by my ear is also seamless within the general 'sweet spot' of the couch.

Matching the sub is much tougher of course. I use dual DIY sonotube subs in the same corner of the room. I have the phase flipped on them to blend into the mains that are ~6' from the nearest walls, and floor to ceiling bass tube traps to cut up the standing waves (which would otherwise distort my ear's judgement AND and SPL meter's reading).

Since the rat shack SPL meter is so inaccurate on bass (and yes I know about the correction chart), I prefer to judge by ear the blend of bass on many diff. tracks of CDs and DVD's -which all have diff. levels of bass mixed anyway, so no 'one' level is ever going to be exactly right in any system.

I certainly would like to set this even more accurately if possible, but it can't be done.

Ever hear a combo DD/DTS DVD w/ diff. surround/sub levels on your system? One's closer to right than the other, even though both are on the same SPL level matched system. But which is right no one can say. Take your pick. Your 'preference' won't be wrong.

Look at the advice of steves (who believes he disagrees with me)...
He says level match w/ SPL meter (ignoring my point being that you can't know you have correctly done this), and THEN tweak your system by ear per source, defeating the whole point of claiming that level matching w/ the SPL meter is so critical!
He then explains how a properly calibrated system should generally sound. Which I think everyone here agrees with, and no one is questioning. Questioning his grasp of my debate points.