The word 'jogaku' refers to 'a quota,' and under the ritsuryosei the Imperial Court compelled Buddhist temples to comply with a Buddhist monk quota to prevent them from wriggle out of taxes.
定額とは、定員のことを指し、律令制においては課税逃れを防ぐために朝廷は寺院に対して厳しく僧侶の定員遵守を求めた。