In working with my examiner to address issues with the claims mentioned in a final rejection of my (pro se) software patent application, I changed one term in the claims from "word1 word2" to "word1 word3", and used a new word "word4" to describe something different that could be distinguished from "word1 word3". Each change occurs 6-7 times in the claims, as the term being clarified is important to the invention. Unfortunately, the words are common English words that by themselves have no specific software meaning—part, region, portion—and are used in a more general way elsewhere in the application.
I can see now that the original spec could be a little confusing, though I truly doubt a person skilled in the art would be confused (and I had numerous clear examples described as well, and marked in the drawings). But seeing how difficult and precise claims language needs to be, I can see the clarity problem from the examiner's point of view (I have made some significant improvements and the examiner has spoken positively about the chances of getting to allowance).
I cannot get a clear answer from the examiner, or the Inventors Assistance Center, to the question now facing me: To what extent can terminology be changed/added/removed from the specification and drawings without it being judged to be "new material"? The new terminology does not change the the invention in any way (How could distinguishing part, portion and region better possibly change it?), but simply describes 3 different aspects (of what the software works on and does) more clearly. I find some parts (portions, sections) of the MPEP that suggest such amendments could be allowed (especially §608.01 subsections o, a, and i), but it is not clear. Google searching has not helped either.
Thanks for any help here.