Refined olive oils, as it has been explained here, are only a colorless, odorless, and tasteless fat. In these conditions they are not desiderable for the human palate, and therefore are not allowed their marketing and consumption.
On the other hand, in the refining process, the virgin olive oil loses practically all the unsaponifiable fraction, whose substances are responsible for much of the healthy properties of virgin olive oils.
To be acceptable for consumption, refined olive oil should be mixed with a virgin olive oil or an extra virgin olive oil to provide it color, flavor and aromas.
The percentages of mixture are very low, between 15 to 10% generally. The mixture of refined oil and virgin or extra virgin is the commercial category "olive oil" and it is the top in sales in Spain. In their labels you can read: "contains refined olive oil and virgin olive oils exclusively", without mentioning the percentage of mixture.
The main condition that must meet the mix is that the acidity must be less than or equal to 1º.
These classes inside the category "olive oil" are not already regulated. By approximation they could correspond to the former categories of 0.4º or and 1º, which were prohibited by law because they confused to the consumer attempting to present the acidity as a quality parameter in the olive oils that were not virgins.
Intense and smooth olive oils are those with different proportion of virgin oils. The industry prefers to make these marketing tricks better than putting them the real ratio of the mixture.
Intense olive oils have more flavor because the amount of virgin oil is greater, and the smooth, on the contrary, have less proportion of virgin olive oil. Therefore, if you decide to consume the category "olive oil" we recommend you to use the intense. This way you will have a greater proportion of virgin olive oils.