multiple costs per item

[butlerinthehome]

Does Square for Retail support multiple costs per SKU?

For example:

1. I have 10 units in stock at $10 cost each.

2. I sold 5, so I have 5 left at $10.

3. I got a good deal on the item, so I buy 50 at $8.

How do I set it up so that I can still track the 5 units I have for $10 and then the 50 at $8?  It's want my inventory to be tracked at FIFO, so the next 5 I sell should be tracked at the $10 cost, then the next 50 I sell should be tracked at the $8 cost. 

OR, is the only way to do this to average my cost across the 55 units and report my new cost as $8.18?

[ACAcatering]

I've not used the SKU system, but could you add a modifier to the item dictating which is which?  It would require manually clicking that modifier on the register I believe, but that's just a supposition.