QOS policing- subinterfaces - percentage-based

[paul driver]

Hello
I came across something the other day that I like to share regarding class based policing.
The client was not seeing the correct BW statistics they expected to see originating from some subinterfaces with applied Hqos policies.

When reviewing these policies on those sub-interfaces they shown to have BW values applied with traffic shapers (TSs) that were set to percentage 100% 

Now my assumption was those applied TSs would take their reference BW value from its respective applied sub-interface value and if they didn't exist, it would take it from the actual physical CIR BW value (specifically applied or not) which then wouldn't really be applicable as two sub-interface would in theory have the same CIR value of its parent single the physical interface.....Surely Not!!!

However after checking (multiple times IOS & XE) it seems to my surprise with TSs when ONLY set to percentage , QOS ignores the ANY applied sub-interface BW values  all together and does indeed calculate off the single parent physical BW value- 

I have since reviewed a QOS press book(below) and it does indeed state to my surprise this is correct what i am seeing.

Example:
policy-map PARENT1
class class-default
shape average percent 100
service-policy CHILD1

policy-map PARENT2
class class-default
shape average percent 100
service-policy CHILD2

interface x/x
bandwidth 300000

interface x/x.100
bandwidth 35000 <--------ignored
service-policy output PARENT1

interface x/x.101
bandwidth 120000 <--------ignored
service-policy output PARENT2

Percentage-Based Policing 
"For subinterfaces, the bandwidth of the main interface is used for the calculation."

End-to-End QoS Network Design: Quality of Service for Rich-Media & Cloud Networks (Networking Technology) (p. 186).