Concerning hops, I'm used to seeing Bittering, at start of the boil, then flavor and aroma some time throughout the boil. In Beer smith the options are "boil, dry hop, mash, first wort, and aroma". So which would be flavoring? If I call them "boil" it affects the IBUs, but if I just call them "aroma" it doesn't affect the IBUs. So what are they?