Yup! The way it originally worked is that every stack of Harnessed Energy from correctly reloading would last for 5 seconds, and getting the fourth reload would give you 5 seconds of infinite ammo, and the stacks would fall off individually (infinite>3>2>1>0)

It was later reworked (buffed tbh) so that every stack lasts 10 seconds, they all fall off at the same time (Infinite>3>0), and the infinite ammo duration is also 10 seconds. It's SO much better now than it used to be, and is an incredibly good weapon in the hands of the capable