Nested ['tabledata']['tabledata'] when loading ['tablefield']['tabledata'] when saving?

Using the most recent dev release, I noticed something strange - when loading the entity (i.e. hook_entity_load() and controller::load()), the field data is nested like:
$entity->field_name['und'][0]['tablefield']['tablefield']
But when saving the field data is nested like:
$entity->field_name['und'][0]['tablefield']['tabledata']

Now, since I am doing a bit of hacking on it, I will certainly concede it may be down to my hacks -- but I am certainly not intentionally attempting to do this. But, can someone confirm this? If this IS happening, is this just some structural quirk or workaround to be compatible with the field API? Thanks. See images below for code and dpm() output inserted in my custom module for hook_entity_load() and hook_entity_update().

function custom_entity_update($entities, $type) {
    dpm($entity, 'on save()');
}

function custom_entity_load($entities, $type) {
    foreach ($entities as $entity) {
      dpm($entity, 'on load()');
    }
}