Currently, every machine will store a backlog of up to 200 items in it's ingredient and output slots. Multiplied by 4+ machines in a row to produce one component, and this can store a backlog of 800+ items, and still take more from the belt. As a result, when you have multiple machines taking items in sequence from a belt, the first machine will hog the items for a long time (and in the early game take up a significant amount of resources which are not being used) before the second machine will get any.

I believe the base game has a feature where the backlog is limited to some multiple of the items crafted/second. I.e., the game automatically picks a maximum based on what is needed, and doesn't take up any more items. Please adjust the mod to use this feature.