A method of setting a control or regulating device of a blood treatment apparatus for an upcoming blood treatment session, the blood treatment apparatus comprising: - a blood pump, connectable to an extracorporeal blood circuit for conveying blood through the extracorporeal blood circuit; - a dialysis liquid inlet line; - a dialysis liquid pump for conveying dialysis liquid through the dialysis liquid inlet line and/or an ultrafiltration pump and/or an effluent pump; - an input device for the user for entering flow values (Q B, Q dia, Q UF) to be achieved or effected during an upcoming blood treatment session, by means of the blood pump and/or the dialysis liquid pump and/or the ultrafiltration pump and/or the effluent pump, and/or for entering a treatment target (d targ) to be achieved by completion of the upcoming blood treatment session; - a reading device for reading and/or storing the flow values (Q B, Q dia, Q UF) entered by the user and/or the treatment target (d targ) entered by the user; - a control or regulating device, configured for controlling or regulating the blood treatment apparatus after the start of the upcoming blood treatment session based on flow values (Q B, Q dia, Q UF) and/or treatment targets (d targ); - a storage device, in which a correction factor (f korr) is stored as a constant; wherein the method encompasses the following steps: a) providing, determining or reading out the correction factor (f korr) from or out of the storage device; b) correcting flow values (Q B, Q dia, Q UF) entered by the user and/or the treatment target (d targ) entered by the user by the correction factor (f korr). - a blood pump, connectable to an extracorporeal blood circuit for conveying blood through the extracorporeal blood circuit; - a dialysis liquid inlet line; - a dialysis liquid pump for conveying dialysis liquid through the dialysis liquid inlet line and/or an ultrafiltration pump and/or an effluent pump; - an input device for the user for entering flow values (Q B, Q dia, Q UF) to be achieved or effected during an upcoming blood treatment session, by means of the blood pump and/or the dialysis liquid pump and/or the ultrafiltration pump and/or the effluent pump, and/or for entering a treatment target (d targ) to be achieved by completion of the upcoming blood treatment session; - a reading device for reading and/or storing the flow values (Q B, Q dia, Q UF) entered by the user and/or the treatment target (d targ) entered by the user; - a control or regulating device, configured for controlling or regulating the blood treatment apparatus after the start of the upcoming blood treatment session based on flow values (Q B, Q dia, Q UF) and/or treatment targets (d targ); - a storage device, in which a correction factor (f korr) is stored as a constant; wherein the method encompasses the following steps: a) providing, determining or reading out the correction factor (f korr) from or out of the storage device; b) correcting flow values (Q B, Q dia, Q UF) entered by the user and/or the treatment target (d targ) entered by the user by the correction factor (f korr). a) providing, determining or reading out the correction factor (f korr) from or out of the storage device; b) correcting flow values (Q B, Q dia, Q UF) entered by the user and/or the treatment target (d targ) entered by the user by the correction factor (f korr).