I had read it and it was why I posted about the difference in the leakage currents. Did you measure their capacitance as well? ESR? I wonder how close some of these parts are to their specs.
By the way, ESR varies with time, much as it does with batteries. Though at least, I don't think this will be much of a problem at modest discharge rates. (Here, it should basically look like whatever the nominal ESR is.)
It is disgustingly apparent over long rates, however -- what would ordinarily be called dielectric absorption, is really ionic diffusion as charges equalize over the deeply porous (activated charcoal?) electrodes. So the leakage has a very long (days) tail, and the ratio of immediate capacity to full capacity (i.e., as measured at a discharge rate of, say, minutes versus weeks -- discounting leakage, naturally!) is surprisingly large, like 20 or 30% (i.e., the absorption recovery fraction).
The same effect, in batteries, limits how fast you can discharge, and especially charge, the chemistry.
On that note, an aside: I think it's neat to consider what's going on in batteries. At modest charge or discharge rates, behavior is linear, ionic diffusion isn't dominant, and efficiency is high. At high discharge rates, there is a large voltage drop through the electrolyte (and any semiconductors or insulators involved -- for example, lead dioxide is a semiconductor, and lead sulfate is an insulator), which saturates the reaction at the facing electrode surfaces, and drives more reaction deeper into the pores. The effect is, as you increase discharge rate, you get more and more current, albeit at less voltage -- less efficiency. This is great news for cold cranking applications, like cars and UPSs.
The opposite isn't true, though: when charging, the intended reaction has a lower overpotential, so it dominates at light charge rates. But a rapid charge quickly saturates the facing electrode surfaces, which undergo higher voltage reactions -- namely, the production of oxygen and hydrogen -- while the deeper pores continue to charge at a modest rate. This directly loses electrolyte solvent as gas (or recycles it, via catalyst, generating heat, in a sealed type), while the bubbles increase resistance further. I tested this recently, on a whim: a motorcycle-sized 12V lead acid battery can sustain over 60A discharge, keeping terminal voltage above 8V; but saturates quickly on charge, climbing to, say, 18V at only 20A. That was only a few seconds test, by the way.
I wouldn't recommend testing this in any lithium technology, for obvious reasons. The higher-voltage reactions (electrolysis of the solvent), and their consequences (gas buildup inside a sealed bag of pyrophoric chemicals, anyone?), are well known.
The same physics ought to be relevant, though. This is good news for RC enthusiasts, but not so much for Tesla Motors.
Tim