What Order are Arrows Used in?

[Barkoneus]

Playing an archer, and I basically have two types of arrows, my standard everyday arrows, and then a variety of bundles with different effects that I save for special occasions (for example acid/fire arrows for trolls).

What I would like is that whenever I use up one bundle, a bundle of my standard arrows is equipped next. In practice, it's either completely random, or based on the age of the bundle.

Does anybody know how this works, or even better how to control it? I tried putting my standard arrows in my first inventory page, but this didn't help.

Workaround is clearly to manually equip new bundles when I am getting low, but I am lazy.

[Gouge Away]

I was told in the past it's in the order of being added (most recently added used first, going backwards) and that seems to be the case, but that could be someone else's best guess.