Incidentally, here's a periodic reminder of IATA Resolution 100, which defines which rule categories are least or most restrictive when combined in an itinerary.
- A "least restrictive" rule category indicates that any rule restrictions apply only within the fare component itself but do not extend beyond the fare component.
- A "most restrictive" rule category indicates that rule restrictions apply to the entire pricing unit. (i.e. if the rule on your first fare allows a Max Stay of 60 days and the second fare allows only 30 days, the maximum stay for the entire ticket or journey is 30 days (Category 7 - Max Stay is a "most restrictive" category)

Most Restrictive category applies to the entire pricing unit
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1 – Eligibility
5 – Advance Reservations/Ticketing
6 – Minimum Stay
7 – Maximum Stay
8 – Stopovers
10 – Combinations
13 – Accompanying Travel
14 – Travel Restrictions
15 – Sales Restrictions
16 – Penalties
18 – Ticket Endorsement
20 – Tour Conductor Discount
21 – Sales Agent Discount
22 – Other Discounts
23 – Miscellaneous Tags

Least Restrictive category applying to each fare component
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2 – Day/Time
3 – Seasonality
4 – Flight Application
9 – Transfers
11 – Blackout Dates
12 – Surcharges
17 – Higher Intermediate Point
19 – Children and Infant Discounts