Example 1
Flying from Berlin to Lisbon via London (all within a single sub-area) on British Airways and TAP, the MSC would be TAP as the second sector, LHR-LIS is longer than the first, TXL-LHR.
Shouldn't the MSC be BA in this example
For travel within a IATA Tariff sub-area, the carrier performing carriage on the first international sector.
Berlin/London/Lisbon are all within the same sub-area (IATA Area2 - Sub Area Europe)
The first international sector would be TXL-LHR operate by BA.