When losing the same is still different

When I was in Las Vegas a couple of weeks ago, something struck me. A friend of mine changed a 20-dollar bill for 20 bills of 1 dollar to put it into slot machines. A normal thing to do if you want to try out different slot machines, and so he did. But the interesting thing came afterwards, when I asked him; well that was an easy loss, wasn’t it? He didn’t seem bothered at all, “only a couple of dollars” he said. This wouldn’t have been weird if he would have said the same thing when he lost 20 dollars at once at the roulette table, but didn’t. He was bothered at the roulette table losing 20 dollars at once, but he was totally fine with losing 20 dollars’ worth of 1 dollar bills.
                The search on the internet didn’t result in many answers, if you google “losing” the only thing results will be about losing weight, which is another interesting subject, but not for today. The internet didn’t answer my question, so I resulted to books; Predictably Irrational by Dan Ariely. I classified this behavior in the irrational thinking category, losing 20 dollars should trigger the same emotion as it is the same action, right? I was disappointed once again, the only thing Ariely talked about was the cost of ownership. Which means that you give a higher value to an object if you own it rather than when you don’t own it. This concept came the closest, but still didn’t explain all of it. It is still 20 dollars and in both cases you owned it, maybe this would apply if it was money which you already won but this wasn’t the case this time.
                Loss aversion is the theory where this phenomenon is probably a part of.  Research showed that we value avoiding a loss more than gaining an equivalent amount. We’d rather not lose $10 than find $10 on the ground. It is not exactly the same, as in our case it is both losing, but in this case our mind most likely sees it as losing $1 dollar over and over again. This would mean that every time we lose we only get the disappointment of losing $1 dollar. The dollars would stack up, but our disappointment wouldn’t be cumulative. So, if we walked away after losing $20 we would walk away with the feeling of losing only $1, as that was the last bet we lost.