Portuguese to English Other Business/Commerce (general)

This is from a customer service questionnaire for Shell corporate clients in Brazil who receive deliveries or fill up at Shell service stations. Under the field "one thing to improve", this client has written: "Disponibilidade de alguns produtos que ficam em B.O". I'm wondering what B.O refers to here - I'm thinking it could be some kind of order form or slip, or some sort of tracking of ordered products but am not sure. This is an isolated sentence so no more context has been provided. Any help much appreciated - thanks very much in advance!