That is wrong. Since HT and ID are both 1st steps. Meaning you loose 3 seconds of re-try (why would anyone continue on a rotation they missed). This would lead to a decision by Drgs to either skip a skill in the rotation to make up for the debuff or continue the rotation and loose the debuff early.
The intelligent drg would probably loose phebo, to shorten their rotation on Dsc (since HT is usually applied 1st in the rotation), or they can loose 15% on a FT which is like what? 20-30pot?
Massively minor.