I have a Janome 6500P and use the 1/4" foot and don't have any problems with it. I also have the Janome 4800 (which was the machine model right before the 6500, so it has the same feet and decorative stitches) and use that one to take to sewing bee 'cause it's lighter to carry.
I don't have any problems sewing the same project on two diff. machines. I think you are trying to "push" the fabric too close to the foot edge....then it's not 1/4".
Hey..I also figure it's my quilt...and as long as all my seam allowances are the same......it doesn't matter. It only matters if you are exchanging blocks with someone else.