What’s the meaning of a disabled form field?

I'm working on a desktop UI that uses a lot of form elements like input fields, spinners, radio buttons etc. to fill out what is basically one big form.

This form has a lifecycle with different check (validation) points that allows the user to put in data at different times (you can save in between). All form fields are enabled from the beginning. To pass through a check point, some of the fields are required. After one passes through, the respective fields will be disabled, because editing is not allowed after passing through (you can go back tho). Passing through the next check point means filling out additional required fields, and so on.

What I'm worried about is how the disabled fields are interpreted?

  • In my case, the content of a disabled field is very relevant. The disabled state says "You're not allowed to edit this value" In the mockup, name and address are already locked because the form is past the "approve" check point.

mockup

download bmml source – Wireframes created with Balsamiq Mockups

  • More often, disabled field can be seen as "not relevant". In this example the disabled state says "This value makes no sense in this configuration". The field says there are two decimal points but it's not relevant since decimal notation is not checked.

mockup

download bmml source

I tried changing the input fields into labels after they are locked, but I didn't like it because there is no indication that a field is editable at some point.

So I'm thinking: what is the intended meaning of a disabled form field?