Hi Misha,
The TargetingIdeaService corresponds to the operation of the Keyword planner which returns
search volume data and trends. If you call the TargetingIdeaService with say a word which is having an incorrect spelling, you will be able to see that this service is correcting the spelling and returning the stats corresponding to the keyword with correct spelling. Ideally, the correction is very close to what google search will suggest while you are trying to search for that specific word or phrase. You could check
here for an old forum discussion about the word with incorrect spelling.
You should see the suggestions like this to an extent while using the TargetingIdeaService, but it cannot be assured that the results from keyword planner and the API will be exactly the same.