It would make more sense to have prices $40, $50, $60, where the $50 plan is always on sale for $30. Then, you effectively have a $30 and $60 plan, and the $40 is a decoy to make $30 seem like great value.
I designed a quick example below. That being said, I have no experience with pricing strategies, and I feel like this example is missing out on users and businesses that would be willing to spend $100.