Do you really use the formula for speaker placement?

There are lots of good discussions on here about improving the room your speakers are in to get the best listening experience. This includes speaker placement. I've moved my speakers all over creation and found where they sound good to me. But then I saw several "speaker placement calculators" and I thought, great, something else for me to tinker with.  :-)    Besides enforcing the standard guidelines of using an equilateral triangle between the 2 speakers and the sweet spot, and the speakers being equally distant from side walls, the formula specifies the optimum distance from the front and side walls. My room is 15.5 ft x 23 ft. The algorithm says the front of my speakers should be a little over 7 feet from the wall and a little over 4 feet from the side walls. The distance between the speakers then is about 80 inches, which is the measure for the sides of the equilateral triangle. Basically, I was about the same distance from the speakers as they were from the wall. I felt like I might as well be sitting between the speakers. For me, this algorithm did not result in a great listening experience. There are about 5 different algorithms, each arriving at slightly different results. Has anyone found success using one of these algorithms, for example, the Cardas algorithm? Or any other algorithm? Obviously, I'll let my ears be my guide. But I'm always open to the proposition that there's something I don't know that I could benefit from.