In this context (generating an additional 1 FP on a 1.9 contribution), rewards that end in 5 have to actually increase the payout by 1, while rewards that end in 0 only have to increase the payout by 0.5. Level 280 for 5 rewards (have fun reaching this one) Based on current knowledge, Arc bonus is capped at 100% so a 5 reward cannot generate more than 10 FP Here are the breakpoints in order of level for the rest of the sub-50 rewards:

A 91% bonus needs the base reward to be at least 50 to see a profit of 1 FP, which doesn't show up on the 4th place spot for many GBs until around level 90-100. For those spots, you may as well only have a level 80 Arc because you need a pretty big bonus to start seeing returns on them. I know you said averages, but in my guild (and I'm sure many others), you have to really sit on these threads if you want to get any spots above 4th or 5th because others who've already leveled their Arcs well beyond 100 are already going really hard on the whole 'making profit in a 1.9 thread' thing. That depends a lot on what spots you're filling at 1.9.

Forge of empires the arc