MikroTik

ihave traffice 64M in bridge as ypu can see
But the totoal traffice = 46M ?


also that

bridge 27M in out Just 20 ? and somntimes the opposite out 30 and bridge 21

Not all of the traffic is forwarded between the pppoe interfaces and the bridge. On ether7, you should see the IP traffic from hosts connected to the bridge towards the internet with some PPPoE overhead (so if there was only this traffic between the bridge hosts and the internet, ether7 out would show roughly 110% of bridge in). But there is a lot of broadcast and multicast traffic on the bridge that is not forwarded to PPPoE, and on the PPPoE, there may be some own traffic of the router that doesn't come from the bridge, or there may even be transit traffic that is forwarded between the pppoe interfaces. So the traffic at ether7 may exceed the one at bridge sometimes.