how generated FBUS2 commands ?

[gsmlab]

I have explanation Fbus2 protocol from Gnokii,
but I can't understand commands for reading IMEI
and phone model from DCT4 phones, which used in original service software
for example:

to phone  7210
03o.bin-> 1E 00 10 7F 00 02 1B 05 15 78 1E 00 10 1B 00 0A ........x......
03o.bin-> 00 03 17 00 41 00 00 00 01 44 59 56             ....A....DYV

answer from phone 7210
04i.bin<- 1E 10 00 7F 00 02 1B 04 05 69 1E 10 00 1B 00 1C ........i......
04i.bin<- 03 31 17 01 00 01 41 14 00 10 33 35 30 38 39 33 .1....A...350893
04i.bin<- 31 30 35 35 36 38 32 34 34 00 01 46 44 53       105568244..FDS

to phone  8310
03o.bin-> 1E 00 10 7F 00 02 1B 83 15 FE 1E 00 10 1B 00 0A ......Ã.þ......
03o.bin-> 00 03 1A 00 41 00 00 00 01 40 54 52             ....A....@TR

answer from phone 8310
04i.bin<- 1E 10 00 7F 00 02 1B 00 05 6D 1E 10 00 1B 00 1C ........m......
04i.bin<- 03 2B 1A 01 00 01 41 14 00 10 33 35 30 36 30 34 .+....A...350604
04i.bin<- 31 30 33 39 35 31 36 34 31 00 01 44 44 47       103951641..DDG

as you can see for reading imei
used frames

in first case
1E 00 10 1B 00 0A 00 03 17 00 41 00 00 00 01 44 59 56

second case
1E 00 10 1B 00 0A 00 03 1A 00 41 00 00 00 01 40 54 52

1E 00 10 1B 00 0A - is a header all is clear with this
two last bytes is checksum
but commands
00 03 17 00 41 00 00 00 01 44
and
00 03 1A 00 41 00 00 00 01 40
have difference
how generated third and last bytes?
seems that answer from phone also depends from this bytes

and I'm confused
why software uses different commands for reading IMEI?
how it generated?

[gsmlab]

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