How can that be 'interpreted' as permitting PICUS to be claimed by a
student in a single-pilot aircraft
Easy, since you ask:
A single pilot aircraft may need multi-crew for certain operations; and it is
not possible to conduct a Test unless
both the Examiner and the candidate
are on board the aircraft
The candidate is not deemed to have been under training if they pass the
test, so PUT not appropriate - what else is there?