A new app could help hourly workers that experience significant income swings -- nearly a third of American households. The app, Even, smooths the irregular, up-­and-­down paychecks of hourly workers into the steady flow of a simulated salary. On good weeks, when users outearn their “average” salary, the company banks the surplus into a separate savings account. When users fall short, they still get their salary, thanks to past surpluses or to interest-free credit from Even. The service charges an annual fee of $156 – which could be preferable to the billions America’s poor spend each year on stopgap measures to smooth their incomes — including $3.4 billion in fees on payday loans alone. Even will be available to all customers by January.