This is Dallas from the Shopify Social Care Team.
Thank you so much for sharing your thoughts of this with me. I definitely see that we are missing this and you have a very good point. Having to mark up each price individually when there are is a large number of items is very tedious! What I will do is create a request to the team who deals with the frustrations from our merchants. I can't promise that they will get back to you when/if they feature is put in, but are you able to give me the name of your .myshopify.com domain?
With that information, I will be able to submit the request for you. Let me know.
Thank you so much for letting me know. I will for sure send this up to our team for them to look into.
You can easily export your inventory to Excel, and add any calculation views there for your adjustments and then import them back into the system when you are done.
Shopify now has the cost of goods in the export, so this is much easier now.
This is what I do.