I just saw this and thought I would offer some more context about why the ephemeris shows what it showed. All planets from Mars outward appear retrograde whenever they are opposite and/or within a certain band of degrees away from opposition to the Sun. The width of that band grows as the planet's distance from the Earth increases, so Pluto's band is wider than Jupiter's for example, and Sedna's is wider than Pluto's. (Explaining why the band increases with distance is hard to do without diagrams so I'll forgo that; if you draw the solar system on paper though you can see it.)
In the case of Sedna, the retrograde band is currently about 82 degrees on either side of the opposition, meaning that currently Sedna appears retrograde any time it is between 180 +/- 82 degrees, in other words between 98 to 262 degrees from the Sun. That means that Sedna currently spends about 24-25 weeks a year retrograde, and about 28-29 direct, meaning its motion is mean direct.
The reason you got the same planetary motion for every line of your inquiry is that you used the consistent date of January 31. On that date every year, the Sun is at about 11 Aquarius. Sedna always appears retrograde on that date during the years you ran the inquiry because during those years Sedna, a slow mover, was always between 22 Taurus and 3 Gemini. That means that on January 31 of all those years Sedna was between 101 (11 Aquarius to 22 Taurus) and 112 (11 Aquarius to 3 Gemini) degrees from the Sun, i.e. within the range of Sedna's current retrograde band of 98-262.
If you had run, for example, a date closer to late Taurus/early Gemini, say May 22 of all those same years, you would see Sedna always appeared direct on those dates.
I should also mention that the retrograde bands for planets from Neptune to Mars are very consistent because of their relatively regular orbits, but those for Sedna, Pluto, and others with eccentric orbits do vary a bit over time (hence my statement "currently" above) because these planets are sometimes much closer and sometimes much further away from the Earth at different points in their orbit (accounting for why Pluto, for example, plods through Taurus but races through Scorpio).
An interesting thing about this from an astrological point of view is that any time a planet or asteroid is opposite the Sun, it is retrograde. To me this fits very well with the EA teachings about the evolutionary intention of retrograde planets to do something one's own way, and about the evolutionary intention of oppositions as "throwing off" what it is time to get rid of.
Hope that is helpful.