PALLETS to FBA and storage fees

We are interested in sending more products into FBA. We have our own brand items that come in a box 30cm x 23cm x 23cm and weigh about 5KG.

Each box contains one item. We are confused by amazon guidelines for shipping these on a pallet as it seems to say on amazon they should be in an outer case on the pallet.

And we are also struggling with what the FBA storage fees work out as. We seem to have found differing figures on storage fee cost on amazon and in their rate cards.

Can anyone help with these points.

Can we load a pallet with one product per box, which is packaged and ready to ship as is. If so does a box label and an amazon FBA id FNSKU also have to be on the box? Or do they have to be boxed into an outer case with the box label on the outer and then the inner boxes have the barcode/FNSKU on them. We cannot get out heads around this.

For a box 30cmx23cmx23cm weighing 5kg what would be the monthly storage rate for oct-dec if they sat on the shelves. We tried calculating cubic foot but the figure came back surprising low so we think we need to resit our maths exams. We read on amazon about a standard parcel size that was larger than this but it only went up to 2KG. The rate card gives higher weights, I think we will blame amazon for confusing us!

Our products are bubble wrapped inside their own box, we prefer this as they are ready to ship and protected, and we are unsure how amazon would ship the item if we packed them inside a bigger box at 4 per box. Reading some of the info on the forums we worry about how amazon would ship them if they were just bubble wrapped.

Thanks!