Yeah I know, but i'd still count it as a first if they arrive at the TBC mat first
Well in all honesty Michael you should (as should everyone else).
The only real reason to track team performance is to gauge the ability of teams. And while luck and factors beyond the racers control do play a large part in the race, luck (both good and bad only goes so far).
Each part of a Double leg is the same as a regular leg. The only difference is that the 2cd half is technically a little tougher since teams don't have 12-36 hour breaks in nice provided areas, with meals taken care of and time to shut down and relax.
For myself I always keep a scorecard of the teams on a even 13 leg playing field for two primary reasons.
1. Its the only way to compare easily between all regular seasons.
2. It more accurate gauges a teams performance and ability