how to correct wrong entries in spell check dicitionary?

It is simple to add entries to the spell checker.

It seems fairly easy to get rid of them, if it was a mistake to enter them.

The dictionary file is located on C:\Users\AppData\Roaming\SDL\SpellChecker

However, when I deleted an entry I observed, that as a consequence spell check did not only pick the deleted entry, but also

similar entries, that are still present in the dictionary file.

I am using no other dictionaries than the default one and I would like the spell check to be a reliable instrument.

Is it possible to use it as such or is there there some hidden algorithm applied by the programm, making it impossible to have a 1:1 relation between the dictionary file and the spell checker?

thank you if any of you has an idea!