[nsp] qos with catos (6500)

[Octave]

Hi,
I am trying to use qos on a 6509 (with PFC). So with Catos (7.5). 
I would like to limit bandwidth of lot of ip (2000) on different vlan.
The value of limit is not the same for all ip.

All I arrive to do is to limit 1 ip with aggregate option like this:
[...]
set qos policer aggregate bd.512.std.a rate 512 burst 1000 drop
set qos acl ip test trust-dscp aggregate bd.512.std.a ip host 192.168.3.1 any
set qos acl map test 3/1-4
[...]
it works really fine. The problem is aggregate option can take only 1024
entries and I need more.

So, I try microflow:

This configuration does not work well
[...]
set qos bridged-microflow-policing enable 3001-3014
set qos policer microflow bd.512.std rate 512 burst 1000 drop
set qos acl ip test trust-cos microflow bd.512.std ip host 192.168.3.1 any
set qos acl map test 3/1-4
[...]
I mean when I make a download, sometimes it works fine (512Kbs) then I
have 11Mbs !? Any idea why ?

Thanks for help
Octave