I only have a THEORY.

Not familiar with the nutrition program and too lazy to look it up right now. BUT the fact the top stuff tastes and smells good and the (older) lower growth is harsh says to me that the Nitrogen is being held in those lower buds.

I know for a fact that since I quit using any additional N other than potting mix (OF), the harshness has gone away. I don't flush either. I give few nutes and feel there is no reason to keep bolstering and overloading the grow medium. The poor plant can only absorb so much.

For further help regarding the other stuff, use the troubleshooting form in my sig.