The reason why Eric had included the two of them in the whole deal thing, was because he wanted this to have smooth sailing and put quickly in action.
After all, if the two of them weren't on board there was bound to be some difficulties, and problems arising, that he would have to spend time thinking about.
In order to not deal with those stupid little problems he had decided to actually take the two of them on board, but that didn't mean that he was going to keep them there.
The two of them were just like snakes, you might try your best to treat them well, and grow them big in your chest, but one day they will follow their nature and bit you in the chest.
Neither of the two is someone who gets satisfied with little, as they have the arrogance and thoughts for more.
Most probably even if Eric gave them 90% of the profits, they would still want that remaining 10%, so much that they would even try to kill him for it.