Well i think it's is still better if the script drinks at a lower amount of prayer potions because it will reduce the chance of drinking twice or even thrice
An example of this happening
My account had to kill a brother at the chest before looting, before killing this particular brother the script started to gather the desired KC. By the time my account reached the desired KC it began to kill the last brother at the chest, at this time my prayer points were 0. The script drank two doses of prayer pots and because the script always drinks @ around 20 points it had to drink for the third time because my account couldn't kill the brother in time. However it wouldn't have drank thrice if the script would drink @ around 10 points or so.
Another negative thing i noticed while running your script is the attacking of random creeps because of the auto retaliate function, five extra cast of a trident a chest isn't very expensive but it does add up.
These are just suggestions, i still love the script even with a few flaws but having those fixed would definately be appreciated