Now that I have turned that off, I still see the variable defined to a value of 1 on the iPhone app, which it allows me to change from 1 to 0. Is this a variable that will be automatically created simply if you have a sprinkle device?
Um, all variables show up in the variables list in Indigo Touch - unless you specifically mark them not to (right-click or uncheck the "Remote Display" checkbox next to the variable in the Variables window). The default database we ship with Indigo has a few variables already created for you.
Is this multiplier of 1 and 0 simply an on/off calculation that is tied in to a script such as on from NOAA for weather cast where the sprinklers will no run or run for a less period than the 30 minutes define on the schedule. I have not been able to find any documentation on this.
The multiplier can represent anything you want it to. Nothing modifies it directly - you have to change it. You could set up some kind of trigger that gets data from the WeatherSnoop plugin about rain totals (NOAA doesn't provide rain data) and sets the multiplier appropriately - but that's logic that is specific to your setup and you would need to implement the trigger yourself.