I am not sure he gets back both the chakra and experience when he undoes the KBs.. During his elemental training with Kakashi he got exhausted when he undid 1000 shadow clones.. if he uses his shadow clones to fight and they get defeated I don't think their chakra comes back to him.. You split your chakra in half when you use a KB.. even Orochimaru laughed at the 3rd for wasting chakra by making a KB during their chunnin exam fight.. Naruto of course has huge amount of chakra but I still feel this limitation has its weaknesses.. We will see how it goes in future chapters though.
when naruto did 1000 clones with kakashi during training, he was not exhausted from making the clones. He was exausted because all 1000 clones were using chakra to train and when they returned, he was overrun with intel from his training.
If naruto makes 1000 clones and sends them in using only tai-jutsu, when they return he should get the info on his enemy and whatever chakra the clones didnt use up.
Kakashi has the least amount of chakra of anyone in the story so far, yet we have seen him use KB a few times. There is no way Kakashi can afford to lose half his chakra every time he uses KB. When he fought Kakuzu, he used a KB as a decoy. I dont believe he could afford to lose half his chakra for a decoy, unless that chakra would return when the decoy is destroyed.
Also, Oro was laughing at the third because he was old and had waited too long in the fight to make KB useful. Oro thought that the third had already used too much of his chakra to be able to use KB effectivly.