To answer the query about date of death, I have a certificate from 1997
where the date of death is shown as 'on or about 31 December 1997' The
certificate was issued by the coroner after a PM but no inquest.
Presumably the coroner decided on the date of death to be entered, after
considering when the person was last seen and the state of the body.
The original query related to English parish records, and I would assume
that each parish did it's own thing regarding burial records (obviously
thinking they were right), having been involved with official records
where it is laid down what should and shouldn't be done and seen the
different interpretations of the instructions, anything can happen!