This appears to be a long standing turbolister bug. When revising a batch of listings, turbolister tends to reset whatever value is currently entered in the each additional field (shipping) when the user does not specify a value change and the existing value is set to 0. Why is this not a locked field if no new value is assigned when editing multiple listings? Currently behavior seems to reset the each additional field to the same value as the cost field when the changes from editing multiple listings are synced.