I finally made a decision to tackle this issue once and for all. After much research I have come to the final outcome that there really isn't much difference other than some mere technicalities.

An offset umbrella has typically aluminum or wood support pole extending up from the support stand and then at the very top bends and angles abruptly out over the shaded area and a canopy is mounted on the conclusion of the pole. 

A cantilever similarly has an aluminum or wood support pole extending up from the support stand however will typically have another piece of aluminum or wood affixed to the key support pole that extends out over the shaded area and an umbrella is then suspended using this second piece of aluminum or wood.

Will there be any added good thing about having an offset patio umbrella over a cantilever? The only added benefit that I possibly could find will be the easy ability of the lowering the height from the bottom to the umbrella with the cantilever umbrella. 

Typically by raising the lever pole you are able to raise and lower the umbrella quite easily. The offset umbrella on the other hand would require a two piece support pole that fit inside of every other with a flag apparatus with holes drilled through the poles enabling raising and lowering of the whole pole and garden umbrella with stand price then keeping of a flag to secure the poles in position. (This is very similar to the conventional market umbrellas)