Working with a man-system

I take care of the administration since the workload spiraled out of control, but Dr Livingstone regularly takes ring binders and writes stuff on the back saying: 'This should go here from now on.'
Which is not cool, because I have my own system of filing stuff and we tend, to put it mildly, hold different opinions on the matter.

We used to have a binder with quotes we make for customers and quotes we receive.
It used to be in one binder. But because the number of quotes going both way have increased, he decided to separate them into two binders.
This is what he came up with:


I was confused as to what was in or what was out. Following conversation took place:
Dr L: ''The arrow pointing away from you are outgoing quotes'.
Mrs B: 'Yes, ok. But which one is that then? If I stand on the left side of the binders one of the arrows is indeed pointing away from me and if I stand on the other side, it points in my direction. So where should I be standing exactly?'
He walks over to the cabinet, not getting my question.
Dr L: 'Look, it is all very straight forward.'
Points randomly at binders.
Dr L: 'This one is in and this one is out. That arrow is pointing outward.'
Mrs B: 'I still don't get it. Why don't you just write IN and OUT on the back. They're not long words.'
Dr L: 'Because it is easy to remember.'
Walks away.

Several weeks later (in the mean time I forgot all about it and did not write in or out on the binder to avoid further confusion), I need to file something again, but forgot how the man-system works.
Dr L: 'It's fairly simple. The arrow pointing to the right is out. Just like handwriting.'
Mrs B: 'I don't follow.'
Dr L: 'Well, it's the same rule. We write from left to right. So to the right is out.'
Mrs B: 'Whatever.'
*writes IN and OUT on the back.