Pet Door HDX encoding calculation

[plambrechtsen]

I am trying to figure out how the HDX Tags are calculated on the Pet Door, have some example tags with their HDX values on the left, and the hex string that is provisioned on the right on the Pet Door. For the Feeders is is stored as normal hex value with 00 03 at the end of the 7 bytes so that is shown as 0003 as it can be ignored. If anyone knows how this is calculated I would appreciate it.

HDX Tag	Pet Door Hex
450041a7b0 0003	04 b6 85 ff e1 17 b7
450041a8c4 0003	04 d2 d2 12 1d a4 c8
450041b0be 0003	04 92 d5 6f 36 93 af
450041fb93 0003	04 c2 62 b6 b5 92 e6
4500422765 0003	04 ae 79 5b a8 8b ff
4500422a1a 0003	04 e9 8a 10 8f f5 4e
450042d6f6 0003	04 e1 14 fb 51 8d 0c
450042e7ed 0003	04 91 16 d3 4a ef cb
450042e817 0003	04 a0 d4 1c e0 06 03
450042f5fa 0003	04 d1 ca d4 77 b6 cb