in the AD2S1210 datasheet*, page 22 in table 19, the LSB size of the LOT High/Low Threshold ist given as "0.09" degrees.
With this value the register content for LOT High would be 2.5°/0.09°= 28 = 0x1C for 14bit,
but for 12bit it would be 5.0°/0.14°= 36 = 0x24.
But there is only one default value for LOT High (or Low resp.) for all possible resolutions - which is 0x23.
So the LSB size would calculate correctly as the maximum degree value (9°) divided by the maximum 7bit value (127):
9°/127 = 0.0709. With this value also the LOT High default register value can be deduced:
2.5° / 0.0709 = 35 = 0x23, which is indeed the reset value for LOT High at all resolutions.
So I can only guess the datasheet value of "0.09" is a typo or a "very roughly rounded value" for "0.0709" instead of 0.07?