[Typhoid]

It doesn't matter on how many per time you do it, it matters how many times you do it, period.


So it's always more efficient and cost-effective to level up something (assuming it already has a 3x multiplier) with [for your example] 14 crankshafts (arbitrary number) rather than 6.

Take advantage of the multiplier. The bonus exp carries over for each level, so you don't just have to go level-to-level. You can skip ahead X levels if you add enough exp in one-go to something.

In short, it's not the amount of exp that matters, or how many items you add, it's how many times you add items to it.

At least, as far as I know.