Hello Vlad
Thanks for sharing your experiences, and let us know how you get along. Just to confirm your suspicion, you are correct, that the policy when applied is applied for each switch. The Cisco documentation I shared in my previous post states the following:
When the shared policer is applied on interfaces or a VLAN with member ports that are across different cores or instances, the rate becomes two times the configured CIR rate.
I hope this has been helpful!
Laz