Shipping - Yes, I know the argument that people pad their per item costs to make up the shipping. I would much rather be able to see my piece prices as what they really are rather than having to try to calculate how much more I am paying across how ever many parts I order. I am usually working on two projects at one time and so I need easy calculations. Promo codes ok too.
Item condition - consistent with Brickowl definitions
Differentiates part mold variations - yes I get that they are "functionally" the same. And all costs being the same (which they should be if you don't differentiate), I'm ok with that argument. For me, if you are charging a higher price on a variation, you should take care to separate the parts.
Comments
Exact shipping. I don't consider that I pad the price of my parts to make up for it. Rather, I use a business model that allows me to charge exact shipping.
Mold variations. I'm very particular regarding my own builds so I always try to differentiate in my store.
Good luck!