If you're then expected to work 200% of the time then you should be paid 200%, with the ability to say no if you don't want to. The actual amount is irrelevant.
Is it how things should be? Probably. But this is nothing close to reality.
If you want to be paid by the hour, be an hourly worker when you clock in and clock out. Then you are paid by the hour.
The whole point of being a "salary" worker is that you are not an hourly worker and you are not paid by the hour. In fact, you have no right to overtime as there is no such thing as "overtime" for a salary worker. There are state by state regulations that can limit how many hours you can legally work in certain professions, for example airline pilots are prevented from working too many consecutive hours, but there are never any regulations requiring you to get more pay if you work longer hours if you are on salary. Work expectations, time off, work-life balance -- these are things you need to negotiate and figure out when you sign that salary contract because it is absolutely not a per-hour contract. So please don't tell people it is -- instead make sure what you are getting into before you sign that contract.