The earnings (in the dashboard) for This week’s stats are wrong.
It says:
This week’s stats
You have earned $26.82
You have sold 3 items
Because it is computed as item price - item fee, not as item price + support price - item fee - support fee.
So each item price is computed as: $13.50 - $-4.56 = $8.94. 8.94 * 3 = 26.82
But in the earnings page it shows the correct value:
$42.93
Total number of items sold this month: 3
Which is computed as 13.50 + 8.10 (6 month support) - 4.56 - 2.73 (support fee) = $14.31 . $14.31 * 3 = $42.93