I think Maryann has it. This was the time when many of the modern surnames were just beginning to become permanent, so it is perhaps reasonable that the ongoing surname was used in official documents with the past names noted.
I was researching William Orchard who died in the reign of Henry VIII but who was noted as a mason (and architect) and quarry owner (and leaseholder) in and around Headington near Oxford. When you read the documents relating to his work and his own quarries, he is often recorded as William Mason, but later this becomes firmed up as William Orchard. His son is noted in the Oxford alumni series as graduating BCL as John Orchard, not Mason,
The choice of Orchard does seem to be linked to earlier generations who were also Orchard or Archard; so it was already an hereditary surname as such, but not yet firmly set as the surname of record.