For the storage boxes used to store intermediate products (anything that can be used to make an advanced product) have a lower limit the storage box must have before it starts sending stored goods onto the belts.
Example, storage box for iron bars has a lower limit of 10, meaning it has to have 11 bars before sending 1 onto the belt (thereby keeping 10 in the storage box).
Rational: many items are needed for repair, but droid won't take it from the belts. So one has to force drop the item from belts to get the droids to use it to repair machinery.
#minimum storage limit before sending onto belts
uneven night
prime path
I split items into 2 lines, one for production and one for items further down the line. I don't think I would want a default setting on a box, I do see the advantage of your statement though.