AT fire in an assault hex

[plloyd1010]

The question of when AT fire may occur in an assault hex came up in our last session. After discussing, parsing, and discussing again, we settled on these points:

• AT fire in assault hex requires the firing unit to activate. Partly because firing at armor entering an assault hex resembles OP fire (which is disallowed), and partly because allowing AT fire as part of assault combat results in double AT fire opportunities.
  
• AT fire in an assault hex does not initiate, or require, assault combat. Functionally it is a separate action in the hex, as would be rallying or digging in.
  
• None of this necessarily applies to the infantry anti tank rules as yet.
  

Anyone else play like this, or have an alternate interpretation?