Do you still decay a full division from Diamond 5?

The blog post that mentions rating decay says that the initial decay is approximately 1 divison's worth. If you are low Diamond 5 (say 1% of the way in) and your rank decays from inactivity, where in Platinum 1 would you drop to? Would it place you closer to 1% or 99%? I want to try to get Diamond this season but know I am going to be unable to play for a week so am trying to figure out whether it would be better to stop at high plat 1 this weekend (to avoid being reset to low Platinum 1 by decay) instead of actually getting all the way to Diamond. Does anyone know how it works?