Even with intricate tunes like "Darn That Dream" which is as intricate as they come, there's a feature on BIAB that amazes me every time I use it, that suggest chord substitutions on any chord in the song no matter what genius wrote the chords in a fake book or whatever.

If you don't have BIAB and or don't use this feature you are losing out on a valuable tool for improving you musical knowledge. Again if 3 chords rock your boat don't get BIAB.

All you need is the simple version. I'm still amazed with version 2010 or something like that. I haven't upgraded in years. Of course the 20,000 sounds on the newer versions bore me to death. I'm only interested in the musical knowledge it provides.

I don't consider adding a 7th or a 9th to a chord a true substitution. An example of a substitution is more like playing a Fm6 before a G7 or G9 chord and someone says try a Dm7b5 instead of the Fm6 is a real substitution. It has the same notes but the voicing makes for a different sound that resolves to the G7 or G9th chord more harmonically and allows for a smoother transition to a Cm7 where there are many tunes that use this progression when playing in Eb usually in a bridge like in the tune, "Give Me A Kiss To Build A Dream On" and another tune that comes to mind is, "Give Me The Simple Live," also played originally in Eb.

R&R, FUNK does not need chord substitutions. You just need to slam the 7th's b5th's and minor 3rd's as often as possible. They work anywhere in the tune if you know which note to make it resolve to. Especially after a dozen drinks the crowd will flip out, have a good time, and you should make a lot of money and have a good time too. I did this for many years in New Orleans, but decided it was time to graduate to something that would motivate the little brain I had left. Ha ha. Back to lurking. I let you guys hash this over.