The IPAP and EPAP values or ranges, as well as all other settings apart from fixed alarms, are always changeable by patients and ALS patients don't have some constant level of respiratory compromise. It's a progressive disease. If anyone ever needs to change their own settings w/o a tech, I can tell you how. Stumble, it makes no sense to have IPAP/EPAP the same for you -- that is CPAP, not BiPAP, and low at that.
As for EPAP and drooling, it's worth noting that if you have a pre-existing obstruction, whether you ever were treated or not, the EPAP can actually be too low at 4, collapsing the airway so you cannot breathe in the full IPAP amount. I'm not saying that's the case for anyone here, but untreated sleep apnea is very common esp. at larger neck sizes.
ECPara, the humidifier should help, feel free to play w/ settings as climate/your climate control settings change. Also, if you have the option on your machine for "manual" climate control (separate setting for heat/humidity), you should use them both.