Is the sandbox api access token supposed to have testing functionality?

I have everything enabled (Rate, Shipment, Label, Pickup, Track, Company, Reference, Product, Address, and Location) for both production and sandbox tokens. I can use the production token and get expected results. Sandbox token is just dumb. Example,
Sandbox token rate request:
"{"status":"success","rates":[]}string(31) "{"status":"success","rates":[]}" "
No rates given.

Production token rate request:
"{"status":"success","rates":[{"courier_id":"blah23855","courier_name":"USPS - First Class","min_delivery_time":1,"max_delivery_time":2,"value_for_money_rank":1.0,"delivery_time_rank":1.0,"currency":"USD","shipment_blah blah""
Rates given

Same exact request, different token. So, is the sandbox token meant to be functional, come up with rates, etc? Or is it a dummy kind of thing?

Also, since I can't test with the sandbox token, can I buy labels to get my integration working and cancel labels and get refunds?

Thank you!