Having different number of bits in very similar commands (up vs down) is very unusual in low cost RF devices. Those things are built as simply as possible using

Having different number of bits in very similar commands (up vs down) is very unusual in low cost RF devices. Those things are built as simply as possible using underpowered CPUs, so I would not expect any sophistication. Based on patterns ("110110110", "1010", "111011101110"), I bet bits are variable length. Long pulse for sync, medium for 1, short for 0 (or other way). So there is always the same number of bits, but the time taken is different. This makes it very easy to decode, and explains the values in the table.