Hmm, that is truly amazing that you never had to replace any. I always have to replace a few. The pipepanic pipes distribution is always the same every 105 pipes (iirc) but the order in which they arrive is random.

I managed to write down from a few good games a configuration that would need at most 7 replacements, probably fewer (perhaps 2). It's not hard. The point is, if you practice it then you could probably get at least a 100 second time bonus and thus get to around 6400, which is probably near the theoretical maximum given human reaction times....

I just never did it because it takes the fun out of the game, you know?