"Makeup Air" requirements and sizing for range hood

For a large gas range, my understanding is that the hood should be sized as 100CFM per 10K BTUs of heat from the range. Taking the 36″ 6-burner GE Monogram for instance, 6 burners x 18,000 BTU = 108K BTU /100 = 1080CFM. GE Monogram hoods are typically rated for 620CFM. Obviously it’s unlikely that you would be using every burner at full capacity all the time, but it still seems like I’m missing something. Is a 620cfm hood sufficient? Secondly, code now says: 505.2 Makeup air required.Exhaust hood systems capable of exhausting in excess of 400 cfm (0.19 m3/s) shall be provided with makeup air at a rate in accordance with Table 403.3\. Such makeup air systems shall be equipped with a means of closure and shall be automatically controlled to start and operate simultaneously with the exhaust system According to GE’s website for their makeup air accessory kit: “Code requirement does not apply to OTR’s” (WHAT’S AN OTR?) “New construction and new additions only, not replacement, as today’s new homes are tighter built and better insulated, thus requiring a makeup air solution. Older homes have more natural air leakage and do not require offset air by a makeup air system.” This is a brownstone with no HVAC system. Do the windows and door count for makeup air? Even though they are not “automatically controlled”? If not, any suggestion for how to meet this code requirement?