You got the imprecision with the calculation. Congratulations!

Yay! Even if that wasn't the intention :-)

the entire concept of velocity is local

Absolutely true. But my doubt is:

Given that the universe is "stretching" at about 68 km/s per megaparsec, it means to me that, considering the earth as the center of the universe (or at least, of the observable universe), for each megaparsec in a given direction i should add ~68km/s until i reach a distance where there is a point which is "moving faster" than light (from the earth prospective) and that i can't reach at the speed of light.

Isn't that right?

Or is the movement of that point just apparent given my position on earth?

P.S. I know Imay sound petulant asking these questions, but hey... free physics lessons :-)