ble_advertising_init() and ble_advertising_start()

Question

I've just noticed that it's possible to call ble_advertising_init() and ble_advertising_start() with params that are quite conflicting. 
 ble_adv_modes_config_t advertising_modes_config =
{
	...
	.ble_adv_directed_enabled = false,
	.ble_adv_directed_slow_enabled = false,
	...
	.ble_adv_fast_enabled = true,
	...
	.ble_adv_slow_enabled = false,
	...
};

err_code = ble_advertising_init(&advdata, NULL, &advertising_modes_config, on_adv_evt, NULL);
APP_ERROR_CHECK(err_code);

err_code = ble_advertising_start(BLE_ADV_MODE_DIRECTED);
APP_ERROR_CHECK(err_code);
 
 The header for ble_advertising_start() says: 
 
 You can start advertising in any of
the advertising modes that you enabled
during initialization. 
 
 But I haven't enabled directed advertising at init and yet I'm able to start in that mode. Is this a bug and what will the behaviour be?

Eliot Stock · Accepted Answer

Sorry (answering my own question), in fact the SDK docs do explain this: 
 
 Disabled advertising modes are
skipped. 
 
 infocenter.nordicsemi.com/index.jsp