One more note on capacity. What the manufacturers spec and how they test may be different from how the charger goes about it, which may yet be different from what you see in real life use depending on the driver in the flashlight and what kind of drain is being put on the cells.
So it’s a lab spec vs theoretical measurement vs boots-on-the-ground. Could argue that the latter is the most important. If you’re draining a cell at a higher amp draw for a nice bright light beam, you’ll get less mAh capacity with most cells than if you run them at a lower current. So Samsung says 5000 but the charger does things slightly different and suggests 4600 but in your light and how you use it you actually get something closer to 4200 or less. It’s all relative and those numbers can vary a lot based on several factors.
Also, the “capacity” that may show on the charger screen for normal charging is usually just how much juice it put in to the cell on that round. That’s different than the actual capacity/refresh/loop cycle functions that are attempting to give you a number closer to the truth. Discharge is the same way…it’ll only show you how much drained out, but that doesn’t mean the same thing. If that all makes sense?
But……the process goes like this: charge at a slow rate until full……rest/recover….discharge at a slow rate until low voltage cutoff….rest/recover (or not)……recharge at a slow rate until full. That’s how the factories do it and that’s generally how the chargers do it for that function. You can do it yourself, too, with just a light, a less-featured but reliable basic charger, and a multimeter…can come pretty close that way but smart-chargers sure are more convenient.