And there's me thinking this was a used plant guide book

I have looked up job rates on the internet and also house builders bible in the past. The two things I found are the customer already has a perceived value already in mind, plus a lot of them get you to price just to check up on someone else's costing.
I think the rates shown vary wildly from way to high, and some way to low. I can't comment on spons but I would be interested to see an up to date copy.