that XyZ Effect is what happens to the object (a building, a ship, a truck) that is HIT by the weapon. This is, in many cases, defined by the objects entry into a terrains _Types.ini.
the **EXPLOSION Effect is the weapon detonating. THAT effect gives the explosion, the shock wave, the debris clouds, etc.
they are set correctly. A Mk.84 is a 2000 pound bomb -- it IS a large bomb, and is, and has been for the last 14 years been using the correct explosion effect.
By changing the effects as has been done, you've, in essence, REMOVED all the explosive material from the bomb casing.
as I've said twice already, put it back to the way it was. If it works, don't fix it.