Im curious as to way it is recommended not to let the Protank II mini go below 1/3 full as stated in various places. I noticed this after many times i've let mine go down almost to the wick and have never had an issue. I do keep the coil clean and dry burn every few days and I also remove one flavor wick from all new coils before use. Is there a real reason and I just happen to be lucky not to have had any issues?