Bug/Unintended Thing with the Tears of the Goddess item line?

Just out of curiosity I wanted to see if when I upgraded Tears of the Goddess to Archangel staff If I could use its 8 mana gain effect and then refund it back to Tears of the Goddess and still have that gained mana, and it did. This put to mind this if someone who could quick spam spells reeaaally wanted to they could sit in the fountain for a little and keep buying and refunding Archangel staff (to reset the finalization timer) so that they could use it to hyper charge the tear, than switch over to a Manamune just before reaching max charge to have a fully charge Muramana in half the time.