UBZII Insurance Index

I've been looking over the UBZII OS thread, and it shows insurance index numbers of 0, 1, and 4 for SD, DD, and 6D respectively assuming IRCs of -4, -8, and -24 respectively. Does anyone know what the accurate 8D insurance index would be assuming an IRC of -32? I'm guessing it's close to +4 like 6D, but I want to be sure.