IHS fee duration for dependents

Hi everyone,

I was endorsed for the Exceptional Talent route. Now I am preparing for the stage 2.
I wonder about 2 things:

  1. I plan to pay 3 years IHS fee for myself and 5 years for each of my 2 dependents.
    I have seen in some former posts that their duration cannot be longer than mine.
    Does anyone know about this?

  2. And what can be the best practice for this? I find paying 3 years fee for my dependents is economically more suitable but I do not want to risk anything at upcoming years (eg. I am afraid a rule change can effect their situation).