Rather than being indexed by the tile's Map16 tile number, this table is instead indexed based on the actual slope tile used; for instance, gradual slopes have 8 tiles (4 left-facing and 4 right-facing) whereas normal slopes have 4 (2 left-facing and 2 right-facing). The slopes in the table by index are:
00 - Gradual
08 - Normal
0C - Steep
0E - Purple Triangle
10 - Very Steep Ledge-edge (from standard object 13)
12 - Upside-down Steep (unused)
14 - Upside-down Normal (unused)
18 - Conveyors
1C - Very Steep
20 - Flat ground