OK, my obsessive number brain note of the day...
When I was around 6-6.5 Qi/sec in passive income I noticed I was getting around .5% Credit progress per tick.
I am now at 7.66Qi/sec and getting less? (around %.38 progress per tick).
Intended behavior? I mention this because I guess I'm in what would be the "end game raiding" mode of Earl here, where it's all about building up credit accrual, then letting it cook for a few days, then rebirthing to cash in for diamonds and do it all again, but faster.