@Alex was correct.

Measurements ended up aligning with posted Iron Heart measurements. And I've got a new pair of IH-888S-21od on the way

I am trying to locate a pair of tag size 33 in this denim. They're out of stock on the official site and I'm in Canada so I've been checking the stock of North American retailers to locate a pair. Several retailers have tag size 33 in stock, however the measurements vary quite a bit from what's posted on the official site.

For example, the rear rise for tag size 33 on the official site is listed at 16.2 while Withered Fig has it as 15.2 and Self Edge has it at 15.5. Normally I wouldn't focus so much on this type of discrepancy but I'm using my existing tag size 33 IH-888S-21 as a reference which has a stretched rear rise of 16.75 and it seems strange that there would be a whole inch difference.

Is there that much variation in batches? I certainly don't think retailers are measuring rear rise any differently.