In module question 15 no where it is written that it is exempt supplies. It is only written that POS is outside India and will be treated as export of service.
However the example you are stating is poorly drafted wherein they didn't explain properly that what performance needs to be done. By the language of the example, it seems its ambiguous whether there is performance-based service or not.
The question is however clear that neither performance is being made on the product since no sample is received nor performance is being done on any person (as to giving him service) therefore it is export.
Don't get confused by the example, the language is ambiguous and they are assuming that it is performance based.