Of course, the double-asterisks are significant:
**This balance may include overdraft transfer protection, line of credit funds and/or discretionary overdraft coverage. Additional amounts included in the available balance may not be available for all transactions.IOW, more funds are "available" but it's not actually your money.
But that's not the tricky part. What's missing here (I've modified the numbers from my own balance today) is a number readily available to the bank: the balance minus pending transactions. The bank knows that (in the present example) $50.76 is pending, but it shows the official ledger balance, not the real-time balance, which should be $50.76 lower.
The goal here is to make the customer think "oh, I have $600 in the bank" when it's actually less, because that increases the chance that the customer will incur the "discretionary overdraft coverage" that makes $36 for the bank every time it happens.
There is no technical reason the bank can't show ledger balance, real-time balance, and "available" balance. And it's not hard to do the math, if you understand how the account works. But quite obviously, BankPlus figures there is money to be made by relying on ignorance. "Balance" to many people means "how much money I have in the bank," and the niceties of pending transactions (themselves a holdover from pre-electronic days - I mean, really, what is "pending" about them?) are likely not stopping to think, "hey, my bank is actually trying to confuse me here."