As in all industries, profit is the motive for the electronics assembly industry. Therefore, understanding assembly cost should be a prime concern. The stakes are indeed great, as approximately 10 to 15% of the $1 trillion electronics industry is assembly cost.
Surprisingly, there does not appear to be a systematic approach to cost estimating in the industry.
I had fun preparing this book for the SMTA. It relies heavily on some software that I authored. If you need to wring a few more dollars out of your process, this may help.