Why do packet and byte rates only account for incoming bytes/packets?

[vellei]

I noticed this snippet in output_csv.c

static char *String_bps(char *streamPtr, recordHandle_t *recordHandle) {
    EXgenericFlow_t *genericFlow = (EXgenericFlow_t *)recordHandle->extensionList[EXgenericFlowID];
    uint64_t inBytes = genericFlow ? genericFlow->inBytes : 0;

    uint64_t bps = 0;
    if (duration) {
        bps = ((inBytes << 3) / duration);  // bits per second. ( >> 3 ) -> * 8 to convert octets into bits
    }

    AddU64(bps);

    return streamPtr;
}  // End of String_bps

So the byte/packet rates are calculated using the incoming data, but what about outgoing data? I was going to submit a PR to add the outbound rates, but I'm curious if there's any reason to not add the outbound rates?