I've noticed that, for any storage entity larger than 1x1, it seems almost impossible for a full belt input to also be set as full belt output. I use both warehousing and the ultimate belt mods, so perhaps it's their size and/or speed that causes issues, but if I have 6 full belts of, say, iron going into a warehouse on ultra fast belts and miniloaders (the first level of Ultimate belts after express), it gives less than that on 6 outgoing belts.
On watching them for a bit (i have no idea how to create and post a gif of this to show you), the input miniloaders start with the items going all the way into the miniloaders which initially provides full input/output, but then they start drawing on the belt further and further away from that point. This continues until it reaches the limit of what I assume is the inserter's reach, at which point there's a sort of snap-back to the inside of the miniloader and the process starts again. This is significantly more pronounced the higher on Ultimate belts you go, as the dark red and purple belts can go all the way to the end of the adjacent belt before this snapback occurs.
I hope I've described this well enough without an actual image, but I'd like to know if you have any ideas on how to fix it? Just seems silly that I need, like, 8 full belts in to fully saturate 6 belts out.
