Your chakra reserves do not grow, what you're referring to is it gets restored, much like if you get tired enough you'll sleep then feel awake, it doesn't mean you can now stay up twice as long as you normally can without actually pushing yourself to stay awake.
Chakra reserves can't be increased otherwise Kakashi for example, would bump himself up to a 5 rather than a 3 or whatever he's been at since the start of Naruto
Edit- Since when is the Narutoverse comparable to a computer that goes out of date every four years, Kishi made the SO6P legendary for a reason.