Hello Martijn, I'm a native speaker of Dutch, and in the Dutch language, the use of the diaeresis is indeed what you describe, to not misread the word.
As far as I know, there are a lot of words that use the ¨ in their plurar form, and many people use them incorrectly (including me) by placing them on the wrong vowel.
It doesn't make much difference to most people if you just drop the ¨ and write it only as e.