Always take material from the bottom. All saddle's tops have a radius (a curve) and are often compensated (like for the second and third strings on your guitar).But looking at the saddle which in this case is cheap plastic. It is bevealed this way and that at the second and third string. Versus the other strings. So if I did mine I would take this piece out and remove material from the bottom to maintain the angles on top. Did yours work anything like that or was yours more uniform across the top. I have heard this is helpful with bar chords.
I would make sure that adjusting the saddle height is something your guitar needs. If it is, it is a fairly simple do-it-yourself job. If the action is too high you may also want to look at nut height, neck bow, and any warping in addition to saddle height.