Oh you're point was right, I was just saying you had errors in your reasoning. I had to explain it to my guild too, lol. As long as you aren't wasting leg respawns and are taking him down to 0 legs at or before his enrage, it is a raid dps loss for your dps to at any point in the fight kill all the legs and force people with cleaves to single target the boss (because as you were saying, there is a finite amount of damage you can do to the legs with the 200% buff throughout the fight).
For the OP, if you have cleavers you should do that. You usually shouldn't bother killing legs if they can't be in the circle because generally it has to do with the specific leg (outer front specifically) and if you kill it then you risk the new leg respawning there. Leave that one up unless there is a chance to dps it from inside the circle. It certainly isn't a raid dps gain to trade 100% to a leg for 100% to the boss.
If you have no cleavers, the only way I can see you making up 25% of the boss's health is by using dps/healers to soak the cleave and running without tanks.