I think you have to understand means "unzila" in 2:185. "Naazil" does not mean send down for the first time as this word is commonly used for rain.
BTW, I have no proof that AlQuraan was send down for the first time in Arabia or to Mohammed.
Hence, fasting has nothing to do with nazala of AlQuraan, inshaAllah.
2:185 The -shahr- (full moon) of Ramadan, in which the Quran was sent down/revealed as a guide to the people and a clarification of the guidance and the criterion. Therefore, those of you who witness the -shahr- (full moon) shall fast therein. Whoever is ill or traveling, then the same number from different days. God wants to bring you ease and not to bring you hardship; and so that you may complete the count, and glorify God because He has guided you, that you may be thankful.
In general the word -unzila- is translated as -sent down- or -revealed-.
Several verses of the Koran mention that water is sent down, for instance in the form of rain.
That does not contradict the reading of verse 2:185 as was suggested.
12:2 We have sent it down an Arabic Quran/recitation, perhaps you will reason.
It is true - we do not have 100 percent evidence that the actual sending down on the person that received the Koran happened in Arabia at that moment.
Though there is enough circumstantial evidence found in the Koran to assume that Mohammad was in an arid area on the Northern Hemisphere. I do not have any evidence that shows otherwise. Hence the first full moon after the summersolstice of the Northern Hemisphere seems to be the right one.
There is no indication that Mohammed lived in a maritime west-coast climate, that is one of the rare climates that has August as the warmest period of the year.
Disclaimer: the study of the Koran is work in progress, every information in any posting on this forum should be controlled by the believers themselves in the best way - verse 17:36.