month names

[Anton]

April would be "incoming"; May would be on its way out, and so it could be talking about the seventh day of the "incoming" April, i.e. the start of April, and the seventh day of the end or later part of May.

Perhaps this means "seventh day counting from the beginning of April" and "seventh day counting from the end of May".

September is mentioned on page 197 in a recognizable way, as is October (and others on page 196) but it may not be the same author.

Yes, unfortunately, the hand in question is pages 177-180 only.