Saw your video on Github and it looks like you’re not publishing to the correct cluster attribute.
You’re trying to change the divisor (302) instead of the unit of measure (300) attribute.
You’re also posting an incorrect Manufacturer code override by typing in the 4000 in that field instead of the Value field.
Everything you need to do to change the divisor has already been explained in the other thread in which you posted. Not quite sure why you ignored the instructions there or in the other thread you raised where I pointed you back to the correct instructions.
You need to write to the following (and make sure the device isn’t sleeping if it’s battery powered)
Cluster: 0x0702 (metering)
Attribute: 0x0300 (unit_of_measure)
Value: 4000
Manufacturer code: 0x1015 (in hex). If this doesn’t work, then use 4117, which is the decimal equivalent.
EDIT: The linked thread makes it pretty clear that you might need zha_toolkit for this. Use that if the change isn’t applied using zha alone.