lots of warmups is a good thing, you want the blood in the muscles and joints nice and warm. as long as your not going too heavy and doing too many reps for warmups its great. All too often i see some guy in the gym who wants to max out, so he loads 135 and does it for 10, then 225 for 10 then 275 to failure(like 4-5) and then 315 for 1 hideous rep. What the fuck is the point of that? it should be like 135x8, 185x5, 225x5, 275x1, 315x? guarantee it'd be more than 1 shitty rep.
maybe your thinking i am going heavier that i should for the warmups? which is exactly what they are for me, i can do 315 for 8-10 good reps, 1 is definatly just a warmup, so no i dont think my warmup scheme is too much.
also going up in smaller weight increments (25-50lbs) is much better for the CNS. Meaning, big jumps the weight feels heavier, smaller jumps, your body adapts and it doesnt "feel" as heavy.