as a reminder, size_offset is >supposed< to offset the size by 'n'. So if size is 32 and offset is 10, the size can be anywhere between 22 and 42. That is not at all what I am seeing anymore. Something's changed, I think.
A handful of examples, all in Darklight Wood:
340252 - a voracious spinner - size 42 - offset 10, but is spawning as 28.
340253 - a poisonous spinner - size 38 - offset 6, but is spawning as 32 (which actually could be correct, but not likely

)
340257 - a frothing snarler - size 29 - offset 4, but is spawning as 35.
340282 - a lumbering crawler - size 127 - offset 27, but is spawning as 53.
<-- way off!
Hope this helps.