What's the deal with the extra space in long hauls?

I've to notice that in my last months of loads, there has been a lot of times where the Full Truck Load is not quite full. There's remaining space on the trailer and also weight availability. For example, I booked a load that was picked up yesterday going from LA to NY. They're paying me the full truck, but the load was almost 14,000lbs and covered half of the trailer, with no seal.

What do you think about reselling this available space? I mean, if I can get 4 extra pallets on my way to NY, its good extra money for little effort. Correct?

I know that times of loading/unloading affect and could compromise the primary load... But if there's a big enough time window, what do you think about picking up Partials to make extra money on available space.

It would be great to hear your thoughts on this!

 

@DUNE-T do you think is a good idea? or too risky?
Another thing that came to my mind after I wrote the post, should I charge for that space as a regular load? It's not quite the same thing, I already got paid for the primary load. Or should I try to make as much as I can for it?

 

I think that it would be easier to make extra money if I resell that available space at a discount to find some Partial quickly to mix with my Primary load. Because if it's in the same lane the cost is almost none and I would make profitable a maybe not so good Primary load.

 

jajajajajajaja... It kind of is... Sorry if I'm being such a Rookie!
I just wanted to know everyone else opinion on this... Especially on the billing of the load. If it's extra why not get a discount in order to fill it up quickly?