Hi @BWYarger, I'd say you can do that by using property sets.
Go to the style manager and create a new Property Set under the Property set definitions on the left:

Make sure you select those two options, otherwise the property set (PS) won't show up in the text editor later.
Add a manual property of type text (set a default value if you want, I chose Sign XX) :

Set property sets auto attach, so you don't have to add this property set to the labels every single time you create a new station offset label. Use the AECPSDAUTOATTACH command for this:

Now, whenever you create an offset label you'll get the property set auto-attached to it:

In this custom field of the extended data tab you can add the text you want to show in the label. However, you need to add the property set to the label before you can see it there.
Go to the label style you are using (in this example I used Station and Offset style), and open the layout tab. Then, go to the editor:

Don't forget to hit the arrow that is pointing to the right to insert the property in the text editor. Otherwise it won't show up in the label. Accept the changes and go back to the model.
Now whenever you edit the text in the PS, you'll see it on the label:

I hope this helps. Best regards!
Camilo Fernández
Civil engineer | Specialist in design, construction, and maintenance of roadways
