On the report filed pursuant to Section 15110, each class in kindergarten and in grades 1, 2, and 3, maintained for a fewer number of school months than the total number of school months contained in the “second period,” as defined in Education Code Section 41601, shall be separately identified. The “number of pupils enrolled” shall be separately ascertained for each class. Whenever the “number of pupils enrolled” in any class is in excess of the standards described in Section 41376 or 41378 the Superintendent of Public Instruction shall, for the purposes of computing the decrease in average daily attendance on account of such excess, modify the factor of 0.97 specified in Education Code Section 41376 by a factor determined by dividing the number of counts made for each class by the number of full school months during the “second period.”