I was not reimbursed for the extra packing tape, even though I was not offered delivery confirmation or insurance, and the tape expense fell within the $11.05 maximum reimbursement.
As MDavis and tsk have said, there is a maximum per item for reimbursement. Postage is only covered for up to 2 lbs, and shipping up to 4 zones away. Delivery confirmation is covered for the $0.75 charge. Insurance covered for up to a $50 item. I cannot remember what the maximum reimbursement for a box is, but it's capped somewhere in the $3 range. You have that break down, both on your receipt and in your report (did you save a copy? print it out?).
Anything extra we purchase, as I understand it, is our own expense.