四分律行事鈔資持記 2.1313

2.1313

不犯中二，初憑他語。師僧無過，受者無戒。若受下，次開後疑。有戒無過。據此止開三位，頻大一位，古師相傳，故《戒疏》中不用亦得。

In the non-offenses, there are two: first, relying on another's word: the master and saṃgha commit no fault, but the recipient does not obtain the precepts. From "if after receiving..." onward, it next permits an exception for subsequent doubt: the precepts are obtained and there is no fault. Based on this, only three positions are allowed; the single position of consecutive long months is handed down by ancient masters, and therefore it is also permissible to omit it in the Precept Commentary.