So if the spec calls for 2.5V you are admitting that “So with the extra 0.5V I’m sure I had seen 3400mAh on all batteries.” if this is the case the tester worked just fine in verifying for your that the batteries are legit. So the remaing question is if the spec termination voltage is X are you also confident that the batteries are legit?
Can I be sure of anything in this world? If not going into the factory, picking out my own batteries straight from the line.
How can you be sure anything you have of batteries, flashlights etc is legit?
Just because it has a high price don’t equal high quality and legit products, just maybe someone who makes LOTS of money selling fake stuff.
So what is your point if I may ask?
I believe the point is that your readings are based on many factors, some of which you have little or no control over. So the readings by themselves don’t really tell you how accurate they are.
Don’t expect 3400mAh on every 3400 rated battery, but I don’t expect 1800 on a 3400 battery either. So the readings should be around the ballpark of what the rating is, or not?
I don’t see anything in this thread about getting 1800mAh on a battery? Did I miss that or is it in another of your threads? And if the reading is on a xxxfire battery then nobody can be surprised at that.
It was an example…On a 3400 battery, I think 2700 is low. I think 3100-3400 is OK.
Every manufacturers official battery specification sheet I've read lists two battery capacities - a nominal capacity and a minimum capacity.
The capacity quoted for sales is always the nominal capacity, not the minimum capacity.
They also list the discharge rate and cutoff voltage that is used to measure that capacity, the cutoff voltages I've seen vary from 2.5 volts to 3.0 volts.
Specifications
Lithium ion Sanyo NCR18650BF 3400mAh battery cell
Nominal Capacity 3400mAh (0.2C, 2.5V discharge)
Minimum Capacity 3250mAh ( 0.2C, 2.5V discharge)
Remember also that there isn't much point in a flashlight in worrying about any battery capacity below 3.0 volts as by that point most LEDs are dim, and if you look at HKJs battery graphs for 4.35 volt batteries there is very little capacity left below 3.3 volts on high for most single LED flashlights at 3 amps.
see: http://lygte-info.dk/review/batteries2012/Common18650comparator.php and select any 4.35 volt battery, then look at the 3 amp curve.
My point was/is that you use the charger to vet that you received the cells you purchased. As you have said (in essence) that you are convinced that the cells are 3400 cells, my point is the cells are what you thought you bought so your question is answered, so why the extra machinations?
You wanted to vet the cells, you vetted the cells, so what else do you need? 
As an FYI my 500 charger draws down to 2.86v then will charge up to 4.22v
even though the same cell might look like more capacity on my 500 then yours that does not mean I would get better performance. as it is the “same” hypothetical cell we would get the exact same performance (provided the environment was identical).
What matters is what is the capacity in use?
And did we get the cell we expected?
When we answer the question “did we get the cell we ordered” then the capacity we get in actual use (what ever that number might be) is exactly that, no more and no less.
I would say that 2800 is too low for a 3400mah battery, but if you are questioning it’s authenticity, then it’s clearly not fake. The capacity is too good.
What I would do is test it twice more, all of the cells, and see how the results come out. If one cell is showing less then I would keep your eye on it, it might be faulty, not fake.
Marc
i have found that both my Lii-500 discharge to 2.82v and then goes into charge mode (if you want to watch the paint dry do it while in 300mAh mode it will give you more time when in the higher / faster modes the numbers jump)
if you really want to take in down to 2.5v you would have to put then into a dumb flashlight and watch it like a hawk
BTW the NCR-BF or B or any non protected cell WILL NOT TURN OFF @ 2.5v its only the manufacturers recommendation if you wanted you can keep draining them down to 0 and kill then in short order
i do not think there is even 1 member here who would willingly take their cells down to 2.5v