He evidently believes that the extant probation procedure does account for noviciation; that is, the first step of the probation procedure is actually taking on novicehood.
The first step for granting probation is identical with the procedure for conferring novicehood (Vin I 82; Horner 4: 103-104).
With all other stages, only full ordination is mentioned, not the novicehood.
And the only feasible way to do so seems to be to treat the first step as an act of taking on novicehood.
They have seemingly been forced to interpret the first step of the probation procedure as taking on novicehood only because they understand noviciation as the sense of pabbajja occurring at the very beginning of the procedure.
Therefore, the first step of the procedure is not meant to confer novicehood upon the candidate but rather to make him appear like a monk so that he can live together with monks who will observe and evaluate him during the probation period.
I argue that there is no need to account for the status of noviciation regarding the probation procedure for former alien ascetics because noviciation is not a legally compulsory step towards ordination nor is probation necessary for former ascetics if they aspire to novicehood only.
Noviciation appears to have never been a legally compulsory step towards ordination, which we can infer from the fact that Pali sources nowhere mention novicehood as a requirement for full ordination (See Vin I 85-91; Horner 4: 108-115), even though the custom of direct ordination might have disappeared in real practice after the novitiate system had been introduced.
Probation appears to be unnecessary for novicehood because: