Under the Alternatives heading there is an option where you can select to use the standard unit when you inventory. Parts with alternate units are usually always inventoried using the alternate unit. If this setting is checked, the standard unit will be displayed for the parts in the Unit column in the list.
If a part has an alternate unit, this will always be indicated with an asterisk (*) in the column to the right of the unit column. To clarify this, the list will show the heading Alt. for this column when you check this alternative.
The Alternate column for alternate units in the list.