FBA Shipping Chargeback Question

Quick question, two different FBA orders to Norway where the shipping chargeback is greater than the cost of shipping, does any one know why please?

Long question, typically if the customer is charged say £2.40 shipping Amazon will give you the £2.40 and then do a £2 shipping chargeback so the shipping is gross and the fees are net, all fine.

We’ve had two orders to Norway, one as follows, other was similar:

Item price net of VAT x.xx
Tax 2.92
Shipping 8.62
Shipping Tax 2.15

MarketplaceFacilitatorVAT-Principal -£2.92
MarketplaceFacilitatorVAT-Shipping -£2.15
Shipping chargeback -£8.97

So they’ve applied the Norway VAT to the order and shipping and claimed it back, again all fine but then the shipping chargeback is 35 pence more than the shipping charge.

Seller support said

I would like to inform that tax charges were charged along while we claim shipping charge from the seller. Hence shipping charge is £8.62 and the shipping tax £2.15. Further I would like to inform that shipping chargeback £8.97 has been charged since it was refunded back to seller with 1/3 rd of the tax.

Which I don’t understand?

Just to add I would expect the shipping and the shipping chargeback to be the same on these sales to Norway.