Vaillant BAI: TargetFanSpeed (0x2400 / d.33) vs. TargetFanSpeedOutput (0x9f00)

[git-developer]

I'm monitoring a Vaillant VSC-196/2. I observed that there are two different values for the fan target speed (configuration file bai.0010003857.inc):

• TargetFanSpeed (d.33, id 0x2400)
• TargetFanSpeedOutput (id 0x9f00)

On my machine, the unit of TargetFanSpeed seems to be rpm; TargetFanSpeedOutput is roughly the half of it:

2022-12-11_06:01:33 bai TargetFanSpeed: 1400
2022-12-11_06:01:33 bai TargetFanSpeedOutput: 767
2022-12-11_06:06:33 bai TargetFanSpeedOutput: 713
2022-12-11_06:11:33 bai TargetFanSpeedOutput: 708
2022-12-11_06:16:34 bai TargetFanSpeed: 1439
2022-12-11_06:16:34 bai TargetFanSpeedOutput: 724
2022-12-11_06:21:36 bai TargetFanSpeed: 1400
2022-12-11_06:21:36 bai TargetFanSpeedOutput: 689
2022-12-11_06:26:33 bai TargetFanSpeedOutput: 679
2022-12-11_06:31:34 bai TargetFanSpeed: 0
2022-12-11_06:31:34 bai TargetFanSpeedOutput: 0
2022-12-11_06:56:33 bai TargetFanSpeed: 1400
2022-12-11_06:56:33 bai TargetFanSpeedOutput: 673

Can someone explain the exact meaning or difference of those values?