Extended Graduated Plan Question — Can I make my payment go down after I am officially on this plan??

hi all,

I'm currently super lucky in that I'm locked into PAYE from 2020 when I was single and fresh out of grad school. My payment has be $0 ever since. I've since established my career more and also ended up marrying a high income earner. I have 130k in student loans left and have already paid about 30k off.

Extended graduated is my cheapest monthly option. Payment would be 588/month. As I've made pmts towards it over the last few years, that number has gone from over 700/month to this.

my question is: once I'm locked into the Extended Graduated plan this summer, if I were to keep throwing an extra 1k a month at these, would that 588 keep going down? or just the balance of the total loans? I do always check to not advance my due date so that it's all going to principle