Just bench press to build chest, upper lower chest is BS IMO, it's the 10% factor again, a decent bench will do 90%, while you can stuff around for another hour to get the extra 10%, once you are elite the 10% might be worth it. For most people the 90% will be plenty.
It's all about return for effort for me, minimal time spend for maximum gains, it's a fine balance to find, but spending time doing sets of 27 different chest exercises or just doing 5 sets of benches twice a week for 10 minutes.
With my schedule the 10 minutes get is for 90% results, not worth to me spending triple the time in the gym to get an extra 10% return.