The Dumb One
Have faith, my Child, have faith. Do not be bewildered.I don't believe it will last, things are seldom that easy.
Doing what you have done has reduced the signal to the TV by at leat 4dB + the gain of the feed-through. So if the TV was on the cusp of too much signal, reducing it is a good thing. Can you get a sig strength and quality reading from your TV and your box and post them for posterity?