I am really struggling to find the right size of rug or mat for my porch. I decided the only way I could sort it was have one made to measure. I was just about to order when I noticed it said "allow a tolerance of +/- 3%". My mat was 84cm square but taking into account the tolerance it could end up being anything between 2.52 cm bigger or 2.52 cm smaller. which really isn't made to measure, is it?