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Since a daylight factor is specific to a particular point, where exactly is this high daylight factor provided?

I ask because the UK School Premises Regulation (1954) specified a minimum daylight factor of 2% in a classroom. Experience brought about a change in this specification in subsequent regulations. First, it was found that this minimum daylight factor was an impracticable solution to lighting classrooms of the usual depth from windows on only one side; the windows had to be so large that problems of glare and heating resulted. Second, it was "recognised that working light could be provided by a combination of daylight and electric light". In the 1981 Guidelines window size was specified as 20% of the window wall area.