I am currently at 29.25 hours of work on the Prairie Rug, but this has become irrelevant due to a major problem with this project.  While punchneedle does go quickly, much of the work I've done on this rug is likely for naught.  You can clearly see the two different colors of green/grey in this photo.  Since most of the area rug will be shown in the room, this is not acceptable.  There will be nothing to disguise it.

I didn't notice this until photographing the rug tonight since the colors look relatively close in person, but the camera really picked up the difference.

I am using a different brand of floss - Sullivans - for this rug because the store I went to did not carry DMC.  I've always used DMC and have never had a problem.  Of course, I've never done large swaths of color in DMC to make a fair comparison, but Sullivans clearly has shifts in dye lots.  There's no indicator of dye lot on the Sullivans floss tags either.  I have three more skeins of this color, but it's impossible to tell if they match the green or the grey without stitching with them.

I might be able to salvage the project by removing the grey areas and trying one of the other three skeins to see if it is a better match to the original. I think it's worth trying this at least.

But, if the remaining skeins don't match the original green, the project might have to be scrapped altogether.  I could try removing all of the green and buying DMC floss of consistent dye lot to redo it.  There are potential problems with this approach, too.  Since I'd be removing a lot of green, it might be worth just starting over from scratch.  I don't know if the fabric would even take new stitching after pulling all those threads and it might take just as long to undo the green as to start over.  It would likely pull the other color threads that are close to the green as well.

I'm just glad this wasn't a huge investment of time.  It's still frustrating and disappointing.  :\

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Update: I took Deb's suggestion and photographed the three skeins I have left on the rug.  They match the grey.  :[

So, it's back to the drawing board...or rather the ironing board to transfer the pattern to a new piece of fabric.  And, I'll be buying a huge matching dye lot of DMC 522 to use.  April suggested taking my work and camera to the store that carries DMC to see if it might match the existing piece on an off chance.  Also worth a shot since I have to buy the floss anyway.  :]

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Update 08-29-13: I contacted Sullivans, and they were very helpful in trying to resolve the issue.  I'm still stuck at this point, but I was pleased with their attentiveness and generosity.