No, it’s not that it can’t be done, it’s just that there will be a ‘standard’ separation of about 5-6mm in the SW, so even if you wanted to move the mics further apart on a one off basis, you couldn’t as that’s the way the faceplates arrive from China in your local shell shop, predetermined by your SW expected gap/inbuilt delay separation.
The other problem with increasing the mic gap is that you increase the definition of the directional sensitivity in the vertical plane too. If your horizontal is out by 15 degrees, on both sides in different directions, you’ll lose the benefits of Binaural Summation in the directional field (Stereo Effect).