Hey Skeolan, in answer to your questions.
The intent was to limit vehicle ranges (quad bikes shorter/flying vehicles longer) and to ease the amount of maths a minimum 1 power was used per trip per vehicle. If playtest feedback suggests this requires balancing (to consider smaller vehicles draw less power) then you could adjust this to half or quarter usage for smaller vehicles.
Secondly, vehicles have a travel limit which is their range so they should expect to be ‘out’ and ‘back’ (APC range is 40 so 20 out and 20 back) if they didn’t take any additional power. However, if you want them to stay out longer than you can assume that they have used some of the vehicle capacity to take portable vehicle batteries in advance or something to that affect (i.e. reduce the outposts power to reflect this).
This is a good example of where the referee needs to make some ‘rulings’. Hope this helps.