Well, that's the first explanation I've ever seen that actually made sense - at least to me. I've been fighting with a block that is supposed to be 8 1/2" but it keeps coming out to just over 8 1/4" to just under 8 1/2". I'd probably just finesse it if it were for me but I'm sending it to someone so I want it really exact. Here's the block at Quilter's Cache and this makes total, total sense.
http://www.quilterscache.com/N/NorthernLightsBlock.html
THANK YOU!!!!!