You’re right!
Works like charm.
[*] [1905] 856: SLES12-Pool sle-12-x86_64
(SLES12-Pool for sle-12-x86_64)
https://updates.suse.com/SUSE/Products/SLE-SERVER/12/x86_64/product/
SUSE/Products/SLE-SERVER/12/x86_64/product/
[B]Repository ID: 1634[/B]
Staging : N
Source : S
Assigned to product: SLES 12 x86_64
Assigned to product: SLES_SAP 12 x86_64
Displaing proper repo ID, looks like good candidate for feature request - What is ID column used for in smt-repos -m|o then ?
Or at least documentation should include a piece of information how to get it 
Thanks for your help!