Great tips! Thanks for the feedback and advice. I had not thought of the boil off difference and that makes sense; I'm sure I would have gone with percentage rather than volume.
AFAIAC, you should ALWAYS look at boiloff as gal./hr., not %. Even though Promash defaults to %, Jeff Donovan advises you to change it to gal./hr. Beersmith only does %. Until that gets changed, I consider it a limitation that makes it difficult for me to use Beersmith.