What a coincidence of receiving a few emails in the past two weeks asking why the commands (such as the barometric settings — KOHLSMAN_DEC and KOHLSMAN_INC) assigned to the rotation knobs and buttons on the FIPs are not working any more. After checking their SaiFlightSimX.xml files, I found another coincidence that the <X52Pro> section in the beginning of their files was somehow removed.
Yeah. I do remember as they reported that the SaiFlightSimX.xml file worked properly without the <X52Pro> section before. I once was using the file without it as well. Not sure since when (probably after some driver versions updated) the <X52Pro> section became necessary in order to have the knobs and buttons to function correctly.
Anyway, to play safe, just make sure the <X52Pro> section is intact in the SaiFlightSimX.xml file whether you have the game controller or not.
Sure, there could be other causes to the malfunctioning of the knobs and buttons on the FIP.