There's something about these kilts

[Cawdorian]

The sett (size of the pattern) of the tartan will be smaller on a 13 oz kilt that a 16 oz kilt, the heavier the material, the larger the sett.

[Planopiper]

Here's the picture of both fabrics. Both are labeled Ancient Caledonian.

The sett size isn't important. It's the difference in colors that I found so surprising.