Your calculation is sound, that is exactly what I had assumed before I actually went out and tested them, that is when it all fell apart. So far this is what I have determined why fast and average speed weapons deal the damage they do. Let's look at Dragon longsword: 1. If strength was taken into account AFTER they normalise, then it's doing too low: (735 * 2.4/3) + 99 = 687 2. If strength was taken int account BEFORE they normalise, then it's doing too high: (735 + 99) * 2.4/3 = 667.2 It is, bizzarely, doing the exactly the average of both calculations With Dragon Battleaxe: 1. Strength after normalise: (894 * 2.4/3.6) + 99 = 695 2. Strength before normalise: (894 + 99) * 2.4/3.6 = 662 The middle value of these is 678.5, rounded gives 679, which is 1 away from the 680 damage shown. So if my conclusions are correct, the ability damage is the average of the damage calculated from both ways. It seems a bit coincidental, to me, that the real damage is pretty much right in the middle of the two calculations. However, the above does not remotely explain why fast speed weapons benefit from + damage more than Fastest (explainable) AND average (not explainable) Perhaps someone could shed some light on the exact mechanism? The reason why this mechanism exists I can only speculate, but probably an attempt by Jagex to balance the fast weapons VS slow ones. Because, if you put the strength inside the brackets, Fast weapons win at 99 strength, because their strength isn't normalised. If you put strength outside of the brackets, Slow weapons win at 99 strength, because of their inherently higher damage. Why not just make all weapons with the same dps pre-strength? Because slow weapons then becomes worse than fast weapons for auto attacks (they get 99 damage per attack, so faster weapons benefit more) Again, only my theory PS. My apologies for the lack of updates, RL has somewhat entangled with my testing. Also, from my recent testing: 1. Dark bow does not remotely do enough ability damage compared to its tier. It is vastly outdamaged by Seercull with Broad arrows (something like 2:3). 2. The damage from EE is "real", as in it does indeed deal damage based on its description, hence the "Just compare its tier" is only a generalisation, it does not apply to EE, Brackish Blade or skilling tool weapons such as pickaxes and hatchets.