Why does it take a while before all solutions are upgraded when a new best is found (rather than just triggering an upgrade right away)? Whats the upgrade schedule? It feels like its been 2 days since the last upgrade.. :P
Also, upgrade might not be the best name for what usually equals to taking away peoples score :P maybe score normalisation or something might be a better term
Cost-cycles thresholds are part of the game's version. This ensures that they are always in sync with the level definitions (including the number and sizes of inputs) and that perfect scores are attainable even if you play an earlier version. The downside of that is, updating them requires some human involvement...