OP should also research the organization's reimbursement rules. Some Swedish companies have tough rules about upgrading business travel. [I suspect it may be related to what I understand are laws about the employer owning the miles if it pays for business travel.] You might not be allowed to use miles or certs to upgrade nor to purchase business class tickets even if they're cheaper than some coach fares, especially if the comparison is for RT fares originating in the opposite direction.