This is truly a sweet price to get from Scandinavia to Houston. I have found the same pricing from Gothenburg (GOT) as well as from Stockholm (ARN). Wide open dates starting in April for 1 day turns or staying for a while. You can use THIS google flights link to play with dates and airports that could work for you.
At these prices it could be worth flying to Sweden for a vacation, taking the run in the middle, then a few more days in Sweden? So many choices and a nice way to pick up a huge chunk of MQMs along the way.
BTW Sweden in April can be amazing or a bit cold. The month of May is better as spring is usually on the way and flowers are blooming. June is when summer really begins and you have the amazing light. Enjoy! – René