That seems to answer the reviewer’s problem.
From the Hal-archive paper https://hal.archives-ouvertes.fr/hal-02066484 , the domain is [0,255]^3 , so it is fairly obvious that 256 is not part of the interval, and that samples of sizes 16^3, 32^3, 64^3, 128^3 and 256^3 from a cube of [0,255]^3 give intervals of those sizes, giving integral divisions.
Perhaps this is not so obvious in the new paper, or the reviewer was having a bad day.
For precision, we might want domains [0,65535]^3 or larger. Perhaps the new paper addresses these.
The new paper might also consider the extent of lossiness. In the thread Help to create a set of "PIXLS.US" color LUTs ? - #56 by David_Tschumperle , “The PseudoGrey CLUT cannot be lossy compressed without losing its pseudogrey property”. I guess the pseudogrey property was below the quality threshold. Is there some analysis of what CLUts can be effectively compressed, or where problems occur?