The 10w only comes into play in freezing weather. The oil behaves like a 10 weight oil at cold temperatures. A 5w will flow thinner at cold temps than a 10w. In Florida, it doesn't get cold enough in most of the state for the difference between 5w and 10w to ome into play. In Minnesota during the winter, I'd opt for the thinner oil. But in Florida, the 10w is fine.
The 30 is the weight of the oil at high operating temperatures.