The FieldComm Group's NexGen committee (soon to be merged into OPC's OPC UA FX committee) requests the addition of a "Good" flavor of UncertainSubNormal.

The description could be:
The value is derived from multiple sources and has the required number of Good sources, but less than the full number of Good sources.

Example:
A device measures 3 signals and votes on them.
If two of them are Good and one is Bad, that satisfies the Required number of Good signals, and the signal value can be Published as Good and used with confidence in control algorithms, but it is useful to know that the voting was not unanimous and someone ought to go figure out why before another one goes Bad and the device's measurement degrades to UncertainSubNormal, which might cause the plant to shut down.

Argument against this suggestion:
Perhaps some other mechanism is more appropriate for this information, such as an Event message or PA-DIM's NE-107 Health status (maintenance required).

Argument in favor of this suggestion:
We perceive "maintenance required" to be a low priority Event that will likely not get attention soon, and this loss of one of set of redundant set of signals is often an urgent matter. e.g. it might require rectification within some time to maintain the plant's SIL rating.