VE, I was using Creatures & Treasures esqe notation, not math.
> not as larger than, but as the "If this attack succeeds it allows another attack of"
In other words, if a bull makes a charge attack on you, you're talking about a triple threat.
The charge would be a gore (Large Horn/Tusk attack) followed by a ram (Large Ram/Butt/Bash attack) and if it knocked you down an overrun (Large Trample attack).
Even if you eliminate that and just say a Bull capable of flipping over a jeep does a charge on you, but has had it's horns chopped off and has no intention of doing a trample, I would still call it a Large bash, but the Large size of the bull vs man sized would mean it does 150% knockback on critical results. (Check out the combat section at the front of Creatures & Treasures).
I'm not saying that a Bull ramming you and a man hitting you with a large shield are identical, I'm saying that the intelligence of the man, and capability to place the shield to best effect, in some ways moderate the results to being equal. There's a limit to how many actual different tables it's worthwhile to have.
As a counter example, look at the martial arts strikes table.
I could easily justify signifigant variation between punches, kicks, knees, elbows and head butts. . . .but all of them resolve on this table.
Even if that seems to be fairly mild variation.
a 1.5m tall Dwarf weighing 75 kilos with a 100 OB in Martial Arts Strikes.
a 3m tall Troll weighing 430 kilos with a 100 OB in Martial Arts Strikes.
A full OB punch from the dwarf vs a full OB kick from the troll, all use the same table to the same results. . .perhaps not realistic, but there is a point of diminishing returns in adding tables to the system.