Damn, i dunno but that sounds like wayy too much coal on top. That'll burn the shisha in an instant. You won't get any good flavor, just burnt taste. 2 QL works perfectly fine for me, especially on SB with a phunnel bowl. 3 QL is alot of coal all at once. The bowl will get really hot and the tobacco will smoke harsh for sure.
Use 2 QL and maybe break them into 1/2's. 2 is usually always a perfect coal number.