@NS User - write off account is not an attribute of FAM Alt Depr, it is an attribute of Asset Type record and Asset record (but not its Depreciation). I m not sure where you see it, but if you have another book for which you are using FAM (and alt depr) your disposal must happen in all books.

Yes, the disposal is hitting the correct write off account in the local statutory book but, where as secondary book it is not

I think pretty much all FAM records are editable via CSV