The figures are all independent of each other, we would not expect them to "tally up." They are simply counts of how much traffic has ingressed/egressed each interface expressed in terms of packets and bytes (packet size in each of the technologies involved are variable size.)
Each interface is capable of both receiving and transmitting traffic - these are all two-way communications links. However, the ingress and egress amounts are independent of each other. It's like a road - just because 50 cars head in one direction, there's no expectation (or requirement) that 50 cars head in the other - the traffic flows are independent of each other. (Routers switches and AP's a like the "junctions" in the road network.)
There is no read across that all the ingress (Rx) values on the LAN/Wi-Fi interfaces should equal the amount that egresses (Tx) the Internet interface (PPPoE) (and vice versa) because not all traffic heads to the Internet. Plenty of it stays local.
As well as the example Chuck cites, here's a couple of others:
If you copied a file from a device connected to (say) LAN1 to a device connected to (say) LAN3, that would tick up the counters on those ports, but no others. As CM explains, a file copying operation is such that the traffic flows are asynchronous so there will be more traffic heading LAN1--->LAN3 than LAN1--<LAN3 for that operation and the Tx/Rx counters would reflect that.
In LAN networking there is a fair bit of "broadcast" traffic used. By definition a broadcast packet is a (single) packet sent from one host to "all others." Thusly, if such a packet is received (Rx) on (say) LAN4, the ethernet switch built into your "router" will transmit (Tx) a copy of that packet out of all LAN ports except the one that received it, both Wi-Fi interfaces, but not the Internet interface. Thusly for that one packet, LAN4 Rx ticks up 1 and all the other LAN/Wi-Fi interfaces Tx tick up 1 and PPPoE doesn't change.
Indeed, until the switch/AP built into your "router" has learned which devices can be reached through which interfaces, this is the default operating state for all traffic - basically, send a copy of all incoming traffic out of every LAN/Wi-Fi interface except the one you received it through. That's a bit wasteful in that it's sending a lot of traffic where it's not needed, so ethernet switches and AP's very quickly learn what can be reached through which interface so they can start to direct traffic only to where it's needed.
The mechanism for determining what traffic gets sent out (Tx) the PPPoE interface and what happens to traffic received (Rx) through the PPPoE interface is different again!