I get the idea behind advantage – the “net” advantage of the system should be a bonus/multiplier to the victory points earned in the system. However, based on the API data available to us, it does not appear to be a factor.
Using the ESI API (/fw/systems), you can see the actual number of victory points in a given system. The API updates with new data every 30 minutes.
In a system with a net Gallente +8% (Gallente 18, Caldari 10 from neighboring systems if it matters), running a Large NVY-1 and a Small NVY-1 during a 30 minute period resulted in a net increase of 300 victory points. There were no other sites run during that 30 minute period, nor were there any kills in the system, if that even matters.
In another system that was Caldari +10% (Caldari 10 from neighboring systems, Gallente 0), running the same Large NVY-1 and Small NVY-1 during a 30 minute period, the net change was also 300 victory points. In much the same way, there were no kills during that period either.
That would suggest that the advantage is not actually working. It does not appear to affect LP rewards, either.
Has anyone seen actual evidence to suggest that advantage does make a difference? Maybe there’s some rounding that is going on before/after the advantage applies that means advantage only matters above a certain percentage? Given that there are 75000 victory points needed to flip a system, the display in-game as a percentage wouldn’t show any appreciable difference between say 0% and 10% when a large plex only moves the needle by about .2%.