Yeah, if theft and destruction of property (though wasn't the cart their own?) is in this guy's merchant book, he's going to be in trouble once he's caught.
I'm also confused by his plan to leave with his caravan full of food and people, without any adventurer escort, in a place recently attacked by orcs. Would the orcs not see this caravan leaving a place they attacked and assume the people from the town would have gone with the caravan and therefore target it?
Perhaps he figures he can make it to the next town and get another escort there but that's very reckless. If he had followed the plan, he'd just have lost some profit. By committing theft, he's risking arrest and his company's reputation (though he probably can bribe his way out of that and I guess it'll still be less of a loss, and he's probably expecting to get away scot-free if the Orcs can finish the villagers and adventurers off). But by moving without an escort, he's also risking his life.
I thought when he said that Sora would regret it meant in future relationship with his company, but what he did is quite foolish for someone who considered his "calculations" to be of utmost importance. He could have threatened to use his connections to blacklist these adventurers, and if that still doesn't work, he should have accepted the losses and gone with their plan since that is the safest course of action. I guess he's not a very competent merchant, but mostly used shady deals to accumulate his wealth and brute force his way to more wealth.