True, the speed split isn't that amazing...but the fact that Melfice is attacking (WSS or whatever), his Sword is attacking (...uh...weak hits! That add up, at least), AND the Regenerator is healing (2000 HP with Alhealer, when average damage is probably around 2400 or so; and this is MT), really does put a strain on Songi. If Songi doesn't nuke something, he's running up against too much pressure overall, and his best damage is out of the picture (Melfice evade fun). Songi's excellent, but...I really can't see Songi stopping the triple threat here. The pressure just keeps piling up, and not killing the parts off makes him suffer, but it's a damned if he does damned if he doesn't situation. Can't go straight for Melfice, as a lot of his damage gets healed while he gets beat; going after the parts cuts off the healing and drops the damage, but he's sufferred enough that Melfice rips him apart at the end, I'd think. If Songi's MT was earlier, he might get this, but...the ST here hurts him. Poison...the small slow effect (I'd peg it about 10%, maybe 20% at best) helps with EXAs, the split of which lets Melfice heal back a bunch more HP, negating one of Songi's actions. While the speed isn't hugely significant, it does make a difference, due to the multiple parts.
It's a good fight, but...multiple parts are too much for Songi without MT.