Costco toilet paper; worth it?

I'm trying to figure out whether Costco's toilet paper is worth the price (compared to a J-brand). Here's my math:

Kirkland 30 roll pack: 1998 yen (total sq. m: 148)--13.5 yen per sq. m

Nepia double ply 12 pack: 298 yen (25m, width: 114mm, total sq. m: 34.2)--8.7 yen per sq. m.

Seems like Costco cost me an extra 708 yen over the J-brand (and the quality and softness seems about the same.)

Did I figure this out right? I've saved a bundle at Costco so far, but I just can't assume everything will be cheaper there.

Can't help you, but remember that 2 ply toilet paper is better than 1 ply!
Buy a few rolls of the paper you find cheaper, to see how good it is.

Costco toilet paper is not the cheapest of the similar quality toilet papers available in Japan. It comes down to your particular preference. Personally I prefer the Costco brand, and although the new size rolls are too large for our toilet paper holders, the overall quality seems higher than similar products we've tried. You'll just have to try them and see which you prefer.