SA Brothers and Sisters,
Dear Syed, Peace Be Upon You My Brother.
Please keep in mind that I do not read Urdu, so I haven't read Dr. Zaman's book. I don't know WHAT he says Saum is, but it appears that he does not believe that it is the ritual abstaining from food and drink and I understand this from the posting of some of his views here by Brother Zubair.
I interpret "Iyyaamaann Mma'adoodatin" as "Counted Days" or it can be interpreted as "Numbered Days". I did not rely on English translations of The Quran when I embarked upon my studies of this subject, I studied it in the ARABIC Quran. The Dictionaries and Lexicons that I used to study the root definitions of the Arabic words are Lane's Lexicon, Dictionary of the Holy Quran by Abdul Mannan Omar and Dictionary and Glossary of the Koran by John Penrice.
Because I do not know what Dr. Qamar Zaman's EXACT conclusions are I have no idea if I have satisfactorily answered your question or not. You said that you HAVE read the book? Perhaps you can post here WHAT his conclusions are and what he says SAUM really is.