The long history is not relevant, but the frequency. Most of Nelson's rules are 1/1000 events. If you don't expect trends to change more often than 1000 measurements, that's too sensitive. I don't know what Elo is measuring every minute, but that probably is too sensitive and most of the hits will be false positives. (Actually, many things will have daily cycles. If Nelson notices them, that's interesting, but after removing such patterns, it will probably be too sensitive.)