I think there is no problem and you do not need to load the $model again.

Sequence is following:

    _beforeSave()

    save() //model in not saved!!!

    _afterSAve() //model is still not saved!!!

    on afterSave dispatching some events such as 
        Mage::dispatchEvent('model_save_after', array('object'=>$this));
        Mage::dispatchEvent($this->_eventPrefix.'_save_after', $this->_getEventData());

    commit() And only now magento save changes in method 

So you evend don't need to use method _afterSave() you can use one of events with following check:

    if ($observer->getObject instanceof My_Module_Model_Price) {