What types are allowed for WhiteLevel (and certain other fields)?

The DNG specification allows "Type SHORT or LONG", but the default value is defined to be "1.0 for floating point images"

Is FLOAT or DOUBLE allowed for this field, or has this field to be omitted in such a case?

A similar question arises for some other fields that aren't allowed to hold a FLOAT or DOUBLE but should be able to (IMHO): BlackLevel, BlackLevelDeltaH, BlackLevelDeltaV, LinearizationTable

ProfileToneCurve is a good example where this has already been allowed.