Questions about SS at 62 and working

[pcunix]

This is from How Work Affects Your Benefits at the SS site.

Also, if you are self-employed, we consider how much work you do in your business to determine whether you are retired. One way is by looking at the amount of time that you spend working. In general, if you work more than 45 hours a month in self-employment, you are not retired; if you work less than 15 hours a month, you are retired. If you work between 15 and 45 hours a month, you will not be considered retired if it is in a job that requires a lot of skill or you are managing a sizable business.

That's in the section titled "Special rule for the first year you retire".

Does that only apply to that section?

I'm asking because I'm self employed and turning 62 in February. Business has been very slow past two years and being able to take some SS would help. I'd earn more than the $14,160 cap, so I wouldn't get the full amount, but it would be a little less than $500 and that would really help - that amount is a little bit more than the shortfall we had this past year due to lowered income. But that "you will be considered retired test" is confusing.

Also related to that: later on in the same page there is this:

Will you receive higher monthly benefits later if benefits are withheld because of work?

Yes. If some of your retirement benefits are withheld because of your earnings, your benefits will be increased starting at your full retirement age to take into account those months in which benefits were withheld.

Does anyone know how they calculate that? For example, let's say that at 62 the full amount was $1420 but because of income I only get $470. After 4 years, I'm 66 and ready for the full amount, which would have been $1800 or so had I never taken anything earlier. How can I calculate what it would be (ignoring inflation, of course) based on the partial benefits in the 4 years previous?