Might be the remaining 4 would be approved for procurement along with the procurement of 24 MH60R ASW helis.
It will take quite sometime to take delivery of the first 6 anyway. And the remaining 4 can come in with more advanced technology that will be developed in the meantime.
From what I understand, the original requirement of 28 has reduced to 22, which had initially reduced to 24 and then 22, the remaining to be supplemented by Guardian drones. It's quite unlikely for the numbers to drop even further from 22 to 18.
Even 22 is too less if you think about it. India's EEZ alone is massive and even then it's only a tiny part of the IOR. We need far more than 22 in the long run, especially when we are seeing no movement on the medium range aircraft deal and the Tu-142 leaving service. At least we are buying a lot of Dorniers.