For aspirational OKRs, we recommend the final scoring ranges to be in orange as the ideal aspirational OKR should be challenging but attainable. A score of 1.0 may indicate a need for more ambitious objectives. With respect to OKRs where you have defined a clear plan of action on achieving them, we recommend using committed OKR's where the final score of green is recommended for a score of 1.0.
All OKRs by default are aspirational in nature. So when you close the OKRs at 100% completion, the system scores it as 1.0 in orange to indicate that the goal could have been higher. Whereas, when you close the OKRs at lower percentage completion(between 70%-90%), it indicates that for an aspirational goal, it is a relatively great completion hence the green score.
You can read more about scoring and aspirational/committed OKRs here: