Which items have you tested? I've tested it with potions and nit worked. But I already had at least a quantity of 2 before using the option.
It could be that it requires the item to be stackable and that it hwas a stack already.
I attempted to use dynamite and found a work-around for this. For the value to stick, you need to use the actual item you are increasing. For example, dismantling an item requires a dynamite. So, once you add 99 to dynamite and then dismantle, will it then be able to placed into the storage.
This feature, however, does not work on item components.
[Edited by hingfu, 12/25/2016 1:07:59 PM]
Please upload or send me your savegame so I can take a look on it. Right now I've had to start a new savegame so I am at the early begnning and just tested the option on potions.
Check PM and I can include a copy