Runway reports are determined and reported by ATC; it is assumed that this based on the TALPA matrix.
Frost is considered wet, but rime is not stated; this problem involves judgement of the difference between frost and rime; how ATC assess and report rime.
Many situations in aviation consider rime to be associated with ice. Technically rime should not be reported, if it is then question ATC; beware of other pilots interpretation.
Thus, if frost use wet performance, but there is some uncertainty reduce the reported condition by one category and check the safety margin, and a further reduction if the OAT is +/- 3C.
If rime = ice, then no go.
If still not clear then Air Safety Report to operator, regulator, and manufacturer.