using the BATT terminal on the switch for a junction works as well as using the terminal on the ammeter, they probably are working from a different diagram or just trying to keep the ammeter connections clean and simple - if the wire length works best, do it the way they say, which should still have a wire from the switch to the ammeter - the volts still go to and from the same place [the battery], doesn't matter which route they go to get there
Bill
