Baselines are auto calculated from existing measurement values in a way that the largest value of some past inverval server as new high and low border of the band. New suspect metrics are now reported relative to this widened band. At the end it means that band could get one alert per week for a violation of one border and the next week that band is widened again. It should be possible to say that the upper or lower border should stay constant at some value (or allow for narrowing). So that the band does not widen in that direction.
Triaged 21-Sept
Yes, I think this is still relevant.
Even with my comment #3, the case is like in Bug 620596 : we should concentrate on better algorithms in the future.