Table IEQc7.1-1 Design Air Speed at 3 ft ht (ft/min)

I thought that I did this yesterday, but lucky for you it didn't post so I'll keep it much shorter on this try. Is everyone just making up numbers for this input? Unless you have a downward blowing diffuser and can easily calculate (estimate) a velocity, or have have horizontally-blowing diffusers close to a wall, there is no way to get this velocity without computational flow dynamics. I could with some reasonable certainty enter a value like "less than 40 fpm" or "less than 15 fpm" etc, but that is not what LEED allows. Is everybody else just throwing something on there and LEED review doesn't call them out? thanks