in v0.12 https://github.com/bitcoin/bitcoin/pull/7081 (by @luke-jr) was merged adding `-bytespersigop` (with default of 20).

this is preventing simple bare multisig transactions from being accepted into mempool when the size is < 400 bytes.  
eg; https://gist.github.com/rubensayshi/ac4f617207f7a50559e85d61c05800be

from 1-of-7 and onwards they are accepted because the ratio of bytes:sigops is high enough.  
also having 2 or more inputs will work because it again tips the ratio of bytes:sigops over.

the reason mainly being that `GetLegacySigOpCount` calls `GetSigOpCount` with `fAccurate=false`.

It looks like changing `GetLegacySigOpCount` to use `fAccurate=true` would cause side effects in the few other places (`ConnectBlock`, `CheckBlock`, `CreateNewBlock`) and simply adding `fAccurate` as arg to `GetLegacySigOpCount` would affect the value stored in `CTxMemPoolEntry.sigOpCount` which in turn affects a bunch of other things.

if (pwalletMain)
        pwalletMain->Flush(true);
#endif
#if ENABLE_ZMQ
    if (pzmqNotificationInterface) {
        UnregisterValidationInterface(pzmqNotificationInterface);
        delete pzmqNotificationInterface;
        pzmqNotificationInterface = NULL;
    }
#endif
#ifndef WIN32
    try {
        boost::filesystem::remove(GetPidFile());
    } catch (const boost::filesystem::filesystem_error& e) {
        LogPrintf("%s: Unable to remove pidfile: %s\n", __func__, e.what());
    }
#endif
    UnregisterAllValidationInterfaces();
#ifdef ENABLE_WALLET
    delete pwalletMain;
    pwalletMain = NULL;
#endif
    globalVerifyHandle.reset();
    ECC_Stop();
    LogPrintf("%s: done\n", __func__);
}
/**
 * Signal handlers are very limited in what they are allowed to do, so:
 */
void HandleSIGTERM(int)