I am.

The basic issue that makes DoT potentially imbalancing is the way the stress is recorded.

That is, say a target has three stress boxes, and takes 3 stress.  Only the third box is marked off.  Instead, say the target takes 1 stress, three times.  The first box is marked off, then the second box as the second stress rolls upward, then the third box.  That's the equivalent of 6 stress!  All it would take to guarantee that this character is taken out would be eight 1-stress hits (which would mark off all three stress boxes and all four consequences up to extreme, assuming the target didn't conceed before then).  So that 8x1-stress DoT accomplishes what a 'normal' attack spell would require as much as 24 stress to do.  It does take longer, of course, but when combined with a grapple that prevents you from doing anything during that time (ie, Orbius), then it's just a matter of running down the clock.

One way to fix this would be to treat the effects of the attack specially, and actually change the impact each exchange.  So the first exchange, you'd temprarily mark the first stress box.  The next exchange you'd transfer the mark to the next box, and so on -- each time removing the pervious mark.  Eventually, mild consequences would be exchanged for moderates, and so on.  Lots of bookkeeping, and the end result is the same amound of effect as an instant attack spell of the same strength.  Of course, then you're left with this question: why not just do the instant attack?

It isn't possible by RAW. We're trying to fix that here.