I have been reviewing a lot of files from other EA's lately and have noticed some things I find odd or incorrect. One that I have run across repeatedly is the use of "R28 at 8.5" batt" in a 2x8 wall cavity, rather than "R28 at 7" batt".
Is there a reason this would be done that I have missed, or is it a mistake as I see it? It results in about an 18% reduction in the insulation layer's effectiveness making the batt function essentially as R23, which in the case I've attached screenshots for is about a 10% difference for the wall assembly in question. I've found the same thing in files on my desk from 3 different EA's so I'm wondering if there is something I'm missing.