All you would do is cut one rep short from each set and you are not going to failure anymore but still stimulating the muscle as much without putting as much strain on the CNS. No drop in weights used is needed.
One interesting observation is also that almost no strenght athletes go to failure and they are alot stronger than most bodybuilders...
IMO from the limited reading I have done, if you do a set of 12 the last 1 rep ad a insignificant amount of extra stress on the muscle but adds a shitload of extra stress on the CNS. The CNS is what takes a long time to recover not the muscle itself. Thats probably the reason why the bulgarian weightlifters can hit the weights 3 times a day and still gain. They never burn out there CNS.
If you use a weight at or above 80% of your 1rm you are going to stimulate the muscle as much as possible with each rep. So there is not any need for the failure part.
Just my oppinion though and Im certanly interested in the opposit view
