Yep!
I am an accountant and this is dangerous thinking as you will need to make a certain gross margin to cover your operating costs, some of which are fixed (such as business rates, shop rent, wages that are not zero hours etc.).
So the last item you sell, you still will have fixed costs to enable you to process the sale.
The risk with selling excess stock at a loss is that you risk running out of cash if you wipe out the profit that you made on the earlier sales.
Andrew