This should work:
Code:
# defaults so is affects everything, but can be overridden by
# more specific sections.
[defaults]
# 'add_to_' concats on to existing param, thus the leading comma
add_to_extra_valid_entries:,oneshot
# oneshot is a copy of status because status itself isn't a list.
include_in_oneshot:status
# Change oneshot from 'Completed' to 'Oneshot' only when
# numChapters is exactly 1.
add_to_replace_metadata:
oneshot=>Completed=>Oneshot&&numChapters=>^1$
add_to_custom_columns_settings:
oneshot=>#fanficstatus
Note that
oneshot now contains 'Completed', 'In-Progress', or 'Oneshot'. (Assuming story has
status.) And that you can use 'Update from Saved Metadata' to populate this column.
ADDED: You have to have the 'Allow custom_columns_settings to override' checkbox near the bottom of the Custom Columns tab checked.