Account for average and median longevity, then recalculate.

I waited four years for a cost of living raise from a concessionary contract, 40% retro (well, I'm still waiting for that), trip and duty rigs (admittedly important), a handful of tangible work rule improvements, and a bunch of other stuff that was negligible. Let's just say neither side got enough and leave it there. Anyone on either side arguing "career expectations" are going to significantly alter the SLI is probably going to be disappointed.