In all fairness, this is obviously a 'custom' arrangement and I think the 'custom' changes are very deliberate (i.e not a mistake, just exercising musical license). Same as doing a jazz version of Jingle Bells or something. I'm not religious but I do love choral gospel music, especially as done by these Black mega-church, 'no expenses spared', choirs. It's a cultural tradition and hard to duplicate unless you grew up in this culture - not impossible, mind you, but difficult. I think you'd be hard pressed to pull it off with an arranger keyboard. First off, you'd need to have the 'gospel' chops exhibited by that organist (and the other musicians) as well as a 'feel' for that type of music (regardless of the realism of the arranger style). Then there is the problem of emulating the choir sounds - that's not going to be easy (understatement ).

What's amazing (about that video), if you think about it, is being able to find that many amateur singers with that sharp a sense of rhythm. That IS the key to up-tempo gospel music.

Just my .02 cents worth (but what do I know),

chas