I dont have the source legislation and have not traced it through
1. But why is the 6 seater Bonanza not considered a passenger transport operation in this case? Is it because aircraft 6 seats or less do not fall under the regime of a passenger transport operation (but under your extract, it does not provide a carve out - so definitionally it captures me and grandma et al going out for a scenic joy flight)
2. Taking your scenario further, I would argue that even if the PC12 was owned by a company, it could legally be flown with you and your mate under the carve out for a (1) (b) "cost sharing flight"