Wrong Outbound Traffic

Hello, Support!

I'm testing Netflow on Catalyst 6509. I've turned on "ip flow ingress" and "ip flow engress" on all needed vlan interfaces.

Inbound statistics work quite well, but outbound traffic on some interfaces is shown wrong. For example, instead of 15 Mbps

Netflow shows about 1 Mbps or even less. Some other interfaces are ok. I've tried to leave only "ip flow ingress" command on

all vlan interfaces and upstreams and ip flow-export version 5, but the situation is same. Interesting fact is that the interfaces with wrong statistics have rather high inbound utilization (higher than 100 Mbps) and lower outbound one (less than 20 Mbps.
Here is some config from 6509:

ip flow-cache timeout inactive 15
ip flow-cache timeout active 1

mls aging fast time 30 threshold 64
mls aging long 600
mls aging normal 180
mls netflow interface
mls netflow usage notify 100 1000000
mls flow ip interface-full
mls nde sender version 5

ip flow-export source Loopback0
ip flow-export version 9
ip flow-export destination XXX 9996

snmp-server ifindex persist

Thank you in advance!