Wall construction dilema

I got the engineer on the phone who drew this window mount drawing:

Initially I was surprised to see a separation with 4 leafs and 3 air spaces and reported here to see what you guys thought of it. The very nice person sounded very sure of his drawing and argued saying that because the concrete leaf and the gypsum leaf were not of the same consistance and thus were not resonnating at the same frequency, it did not mind at all to have 4 leaf. It would have been worthless to have 4 leaf of the same mass at the contrary. Now I come back to my problem which was a wall made of hollow concrete block, I had been told here that because the blocks already obey the system of mass-air-mass creating a second leaf made of gypsum and leaving some air+insulation would have been even worse that to leave the wall as it was. It would have amplified the bass frequency. This person told me that the difference between a plain block and an hollow one was only of 3db and that I could have done another leaf on BOTH side of this wall to improve TLS since the leaves were of different consistance. I am confused as this person has very good references. I hope he is here reading this thread. Thanks Alex