請觀音經疏闡義鈔 1.81

1.81

「等觀」下云云者，應通前結數。前約自他護法等，能所合辨有七十八；今歷四教觀法觀之，則有三百十二請也。

Where it says "and so forth" under "equal contemplation": One should combine this with the preceding to calculate the sum. Previously, based on oneself and others, protecting the Dharma, and so forth, the combination of capacity and object yielded seventy-eight; now, contemplating them through the contemplation methods of the four teachings, there are three hundred and twelve invocations.