Curious: Faster to Transform then delete rather than Transform with delete true

While using:

ScriptContext.Doc.Object.Transform(self: ObjectTable, objectId: Guid, xform: Transform, deleteOriginal: bool) -> Guid

I’ve noticed it is faster to:

ScriptContext.Doc.Objects.Transform(guid, False)
ScriptContext.Doc.Objects.Delete(guid)

than:

ScriptContext.Doc.Objects.Transform(guid, True)

and I am just wondering why that would be?

Thanks