I'd say that is a design decision to have the boosted discharge curve like that, to try to enable the battery gauge function? At least, they could swing it that way... Perhaps it also keeps the efficiency higher by reducing the amount of boost and current drawn from the cell as its input voltage decreases, compared to trying to keep the voltage fixed at exactly 1.5V as the source cell voltage decreases. ESR would ensure the cell would die even quicker if they kept the voltage at 1.5V, thus exponentially increasing the current drawn from the cell as the voltage decreased. It seems like a pretty good design, it's just a shame there was so much dishonesty, lack of real info, false claims, and marketing BS which went along with it. And of course it's trying to solve a problem that doesn't exist (and failing).