With the low cut off at 2.75 V the voltage you get a weak battery warning at will be between about 3.2 V to 3.5 V from most vapers depending on cells and power lever. It is the voltage under load not the voltage at rest.Nothing wrong with it unless you can't vape any more because of the sag. No reason to set everything to the lowest possible setting and not be able to vape it. We had a guy here want to send his SMY back because he couldn't get his vape at 100%. Well anyone vaping at 30-50w is isn't going to be able to vape it at 50% if you set everything to the min.
Not only that but the actual stored power in 3.0 down to 2.7 or 2.5 is so marginal it's not even worth worrying about.
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EG:
Running at 75 W, with efficiency of 85% you need 88.23 W from the cells, say your cell is 3.5 V that would be at least 25 A (I = P/V). With a cell of 20 milliohm IR that would be a sag of at least 0.5 V (V = IR) so your voltage under load is less than 3 V. Because of that sag you need more current, run the numbers a few iterations and it ends with your 3.5 V 20 milliohm cell delivering 88.23 W would at best be trying to supply 30.54 A and sagging to 2.9 V, but in the real world it would sag far more.