Have you ever been confused when researching your family history and come across so many different types of entry within a single register?
The incumbent or parish clerk making the entry would have decided what information was to be included, this can be seen by the change of writing styles and name of officiating minister. Some incumbents were mindful of detail whereas others recorded the basics that were required by the church administration. Some even just didn't bother to record anything.
The attached book The Parish Register (1910) is an interesting read and interprets the guidelines laid out by the church and the civil registration system for recording entries within the parish register from its earliest entries to the format of the modern day entries.