I also hold like you, that hakaras hatov means reciprocating in kind.
One time, I was down and out. No job, no money, and major shalom bayis issues. My good friend was a real lifesaver. He convinced a business associate of his to give me a job. I started as a salesman, but I was able to build myself up to be head of the sales department. I was b”H able to pay my bills, with something to spare, and earn back my wife’s respect.
The problem was, how can I possibly repay him in kind? He was successful in his job, with a great marriage; a bottle of wine or a heartfelt letter just wouldn’t do the trick.
So I spread rumors about him that he was involved in a ponzi scheme.
His business associates no longer trusted him, so he couldn’t do business and he lost all his money. His marriage was, b”H suffering terribly.
So I was able to convince my boss (with whom I had since become partners) to hire him as a salesman.
B”H, hakaras hatov lemehadrin!
All because I hold like Popa, that hakaras hatov means you have to do exactly the favor that was done for you, in order to show your appreciation.