You could also set the fillTypes directly.
<fillTypes>
<fillType name="alfalfa_windrow>
<units>
<unitSet name="imperial">
<unit name="ton" precision="1"/>
</unitSet>
</units>
</fillType>
</fillTypes>
Do the same for dryAlfalfa_windrow (as well as any of the other balable types such as straw, grass_windrow, dryGrass_windrow, etc).
You could ALSO make a group for all of those and set it at group level.
<fillTypeGroups>
<group name="grass" title="Grass"> (you could name it anything)
<units>
<unitSet name="imperial"/>
<unit name="ton" precision="1"/>
</unitSet>
</units>
</group>
</fillTypeGroups>
<fillTypes>
<fillType name = "alfalfa_windrow" group="grass"/>
<fillType name ="dryAlfalfa_windrow" group="grass"/>
</fillTypes>
Point is, you have quite a few options at your disposal. But I will look into the issue. Thanks for bringing it to my attention!