[P235 16Ga AirStrike not sinking nails all the way]

On mine there's a little knob on the side that turns and if you look at it closely, you can see 2 images of a nail, one lower and one higher. Turn the knob in the direction you want till it sinks the nail to your desired depth 

[Ryobi P 507 6-1/2in cordless circular saw]

Am I an IDIOT OR NOT SPEAKING ENGLISH!!!!! I have asked a simple question on multiple websites and can't get a very simple answer. The question is "" how many cuts on average can I expect to get per charge from a Ryobi P 507 6-1/2in circular saw ""?????? Every place will tell me how many the 7-1/2 model will get (325) . But I cannot get an answer to my question. Does anyone know the answer PLEASE,I REALLY APPRECIATE IT