It depends on what you look at I guess? compared to one year earlier he lost 7% of his Patrons, but:
He had 2733 Patrons left in August, and 2816 in September. That means during September he gained 83 Patrons. You can literally see the September line being higher again in the left image. The peak was higher though - but I would think if Graphtreon uses the baseline for comparison, that one is more significant?
If you look at the curve more closely, it is mainly due to the fall of Patrons at the end of September being smaller than before, so this might suggest that most people not happy with the current situation left already, and what we see now is somewhat of the die-hard-core of Patrons - who knows?
For Graphtreons money calculations - I have no idea if Graphtreon can still track that because BD removed that info from his Patreon account, as visible in the charts too.
But before he did so, the pledge per Patron was on a slow rise - so my guess is, with no new data, Graphtreon assumes, that trend just continues indefinitely, so every month it assumes everyone just gives BD a little more - forever. And of course, every new Patron pays the average of what Graphtreon knew last to be true .^^
The high rise in money per Patron might even indicate, Graphtreon looks at both curves somewhat independently - so with fewer Patrons, for the money climbing like it did last when available, everyone obviously has to be upping their pledges all the time.
So, for Graphtreon to just show what you want to be displayed, wait until you have a good run, then turn down any info it can analyze and your charts are good.