The starting value is not incorrect. I moved from Quickbooks Desktop earlier this year and was using the average cost basis method.

When I imported my Quickbooks Desktop file to QBO this summer, it converted to FIFO. Looking at the opening quantity and balance, it's correct. Exactly the numbers from Quickbooks Desktop.

You can see all the purchases and sales this year, but when you get to the end, even though all the inventory has been sold, the value with zero quantity on hand is non-zero. I don't understand why. 

I'm loading an example spreadsheet of the part in question. This is the valuation detail report for this year. You can see the first line is the inventory value from Desktop that QBO assigned during migration. I've taken out the names and document numbers for privacy. You can see there are a couple of places where the quantity gets to zero but the value is very much not zero. Makes no sense to me.