Some steering wheel control button needs common increasing data both at Down Button Message and Up Button Message.
This option is used to give common increasing data both for Down and Up Button Messages.

Example:
Idle Message is
Dur: 0 Len: 4 sID:50 dID:68 Data:AB CD
Down Button Message is
Dur: 0 Len: 4 sID:50 dID:68 Data:3B 08
Check on Use Idle Message as Up Message

When the button is pressed and released, the messages are sent to the radio though BSGd like below.

Len: 4 sID:50 dID:68 Data:33 08
Len: 4 sID:50 dID:68 Data:34 CD
Len: 4 sID:50 dID:68 Data:35 08
Len: 4 sID:50 dID:68 Data:36 CD
Len: 4 sID:50 dID:68 Data:37 08
Len: 4 sID:50 dID:68 Data:38 CD
….