Morris, here's an actual table output from my dis-assembler. The last byte pair seems to be repeated in every case. I think this must be the same case as the 3D tables - IE, it's used for the last point calculation. I'll have to read the interpolation routine in detail.
EDIT: Actually, that's all wrong. The first byte is the number of data points in the table (just like the point-slope tables). The first byte always seems to return 0x00, and the last 0xff. There's no repeated bytes. Correct table format is now updated below.
Code:
Table11:
.byte 5 ; number of points
.byte 0x48, 0x00 ; point 1
.byte 0x48, 0x2f ; point 2
.byte 0x4b, 0x34 ; point 3
.byte 0x7d, 0x3e ; point 4
.byte 0x7d, 0xff ; point 5