KarinsDad said:
In order to get "the same bonus as the attack that dropped the previous creature", the previous attack had to have a bonus (even a negative one).
There's no such thing as a negative bonus in D&D.
A bonus is "a positive modifier to a die roll".
A negative modifier is not a negative bonus; it is a penalty.
The low BAB, prone character did not have a bonus on the attack that downed the previous opponent. He had a penalty.
However - this is where one needs to be careful with one's reading of the Cleave feat.
"at the same bonus" doesn't, in fact, mean "exactly the same total modifier as was applied to the last attack".
There are a whole lot of situational modifiers that may not apply to the Cleave attack, or that may apply to the Cleave attack where they did not to the initial attack.
Higher Ground bonus. Invisibility bonus. Smite Evil bonus. True Strike bonus. Bane weapon bonus. Racial enemy bonus. Charge bonus.
All of these are situational. If you used a True Strike, Smite Evil, Goblin-Bane attack on the Medium evil hobgoblin from your Large horse, you get a bunch of modifiers on that attack roll that are inapplicable when you Cleave into the Large, neutral Dire Wolf standing next to him.
"At the same bonus" serves to distinguish the feat from those that give an extra attack "at your highest BAB". Use the same iterative bonus from BAB as the attack that dropped the opponent, and add
applicable modifiers.
So your low BAB prone guy makes his Cleave attack at the same low BAB, and adds the same prone modifier.
The CDG guy uses no BAB, and adds applicable modifiers.
-Hyp.