I have also heard "pole, pole" used to mean "slowly, slowly" when used twice in a row.

the word ''pole'' simply means ''sorry/i am sorry'' pole can be used for both big & small problems. from the native speaker

I'm not a native speaker, so it's just my opinion. I used to stay in Kenya, and I heard people saying this word so many times, almost everyday. They say "pole" when someone has a problem whichever big or small. And the other person replies "asante". I hope my comment can be useful.