I love the base concept of Customer Capacity. If you don’t have enough shopping baskets and cash registers, you will create a bottleneck that limits your customer flow. I feel there could be a little more logic behind the calculation, though.
For instance, if you have a gift shop with 2 cheap gift, rounded shelves, shopping baskets and a checkout-counter, you are hitting your 30-capacity limit and that all makes sense. But if you try to expand and add one expensive gift, rounded shelf, it suddenly reduces your store capacity to 15. I don’t think your cheap gift sales should be punished for adding expensive gifts.
Perhaps there could be two levels of this calculation. The things that are required for customer flow like cash registers and shopping baskets set the overall building limit. But each item’s chance of being bought would be limited based on how many shelves you have for that item.
So is you have enough baskets/registers for 30-capacity, if you have 2 rounded shelves for cheap gifts, but only 1 rounded shelf for expensive gifts, your cheap gifts would sell at “30 customer-capacity” levels but expensive gifts would sell at “15 customer-capacity” levels.
This would also be really nice for adding extra items to your 75-capacity store without needing every item to hit 75-capacity. Your main items would still sell at 75-capacity while your bonus items would be limited, but still helpful.