More Trustworthy Confidence Ranges

Improved

• The default confidence_level is now 0.80, previously 0.95. This matches the range our models genuinely produce, so the returned band reflects real uncertainty rather than being stretched to a level the underlying models cannot support. Requests that pass confidence_level explicitly are unaffected.
• The ensemble model now gives more weight to the variants that forecast best on our data, instead of averaging all three equally.
• Ensemble confidence ranges are no longer widened past what the underlying models actually predict, so the reported range is one the models genuinely support.
• Confidence ranges are now steadier from one period to the next on shorter histories, where they could previously swing widely between neighbouring periods.

Fixed

• Fixed the standard model falling back to a fixed placeholder confidence range on many datasets instead of a real statistical one. The affected ranges were far narrower than the true uncertainty, which could make forecasts look more certain than they were.
• Fixed yearly seasonality being applied with a shortened, out-of-step cycle on roughly two-to-three year monthly histories, so seasonal patterns are now modelled against the correct yearly period.
• Fixed a data-sufficiency check for seasonality being calculated and then ignored, which could allow a seasonal model to be fitted on too little history.
• Expanded regression coverage around confidence ranges, seasonal periods, and model selection.