Please, keep in mind that the listed prices are higher (0.01 - 0.05) than actual payment to prevent transactions failure for the case when two users buy the same tank simultaneously. The price for the second buyer will be higher than he sent, so his transaction will be failed. Overpayment is impossible as excessive funds are returned to the account balance in all cases. Feel free to read our smart-contract: 0x14a3f4795076c0ae67c2aa9efc10e58427a00dff Check our telegram-channel: https://telegram.me/ethertanks We suggest you cashout your balance as regularly as possible! Your balance on the page "tanks" may be different.