You should learn to apply logical thinking to your comments Flionheart and especially the conditions this was under. But I expect you wanted me to write a *** essay about it on the Tag section. I posted this screen shot to show the potential it has, and no it isn't shopped as I have no idea how to use photo shop either.
The difference between a flat out 10% increase over TP Bonus is that the higher the raw base DMG, the more that 10% will do for it, as TP Bonus doesn't completely work in that way.
The conditions were obviously Groundskeeper's in Sky, Sneak Attack was used @300TP, and of course DA did kick in.
I have never in my many years of using Hagun seen spike DMG this high on normal monsters, and trust me, I've killed a fair few of these in my time, before you started playing this game I'd imagine.
It still averaged higher than Hagun when DA did not kick in, and that was at around 100TP or whenever SA was ready.