Indexed PNG palette is randomised?

[rich2005]

A little bit of a hunt around Is it related to this post

https://www.lemkesoft.info/forum/viewtopic.php?t=3936

editied out this part 16 grayscales that those models of Kindle can display correspond to: #ffffff or, 255 255 255 #eeeeee or, 238 238 238 #dddddd or, 221 221 221 #cccccc or, 204 204 204 #bbbbbb or, 187 187 187 #aaaaaa or, 170 170 170 #999999 or, 153 153 153 #888888 or, 136 136 136 #777777 or, 119 119 119 #666666 or, 102 102 102 #555555 or, 85 85 85 #444444 or, 68 58 68 #333333 or, 51 51 51 #222222 or, 34 34 34 #111111 or, 17 17 17 #000000 or, 0 0 0 The final image needs to be saved in a 4 bit (16 color) PNG-8 format with the above exact indexed values.

I can make a Gimp palette easy enough, it is a text file

Code:

GIMP Palette
Name: 4-Bit Grayscale-reversed
Columns: 16
#
255 255 255
238 238 238
221 221 221
204 204 204
187 187 187
170 170 170
153 153 153
136 136 136
119 119 119
102 102 102
85 85 85
68 68 68
51 51 51
34 34 34
17 17 17
0 0 0

If I take an image and convert to indexed mode using that palette

   

The colormap keeps that order

   

and checking the properties with Imagemagick it looks consistent. Nothing scrambled.  
I do think there might be a bug in the png export, Use automatic rather than 4 bit otherwise the result is not indexed.

   

..but then I have nothing kindle to try it on.