Originally Posted by
CruiserCLE
One of the experts can probably give more context or pull the fare rules, but highly likely that the discount business buckets (especially intl) have some sort of advance purchase requirement. So even though you "see" availability down to PN, the Z and P fares likely have 14,21,30+ day purchase requirements, or minimum stay that you are not meeting with your quote for a ticket ~10 days out.
Correct. The P and Z fares both currently have a 60-90 day advance purchase requirement, except for one extremely date-limited P fare that won't fit the parameters.