Hover the ? button to see where you can find informations on PoB (all is in calculation page)
If you change those values after first calculation, you need to check PoB to have your new attack speed and make a new calcul. This part is only needed to help you fine tuning your atk speed after calculation.
This calculator is pretty accurate. But notice that : i took a small margin of security for rounded values. Results in game may be a bit different accordind to your network setup (ping, predictive/lockstep, packet loss...)
Server seems "store" missing projectiles, the first attacks have the good amount but the more you attack in place, the more projectile you lose in bad setup. It is good for us if we move pretty often :)
Big thanks to Cowin13 who made a lot of poison testing for me. Thanks to ThisIsProphet for his tests too, it helped me a lot inderectly. And Thanks to all of you for all your messages.