Automatically generated index (paragraph, library, words)

[buenos]

When writing a book in MS Word, I can generate an index (key words and page numbers) using the automatic indexing feature in Word.
Basically, I write a text file with a list of key words I think are important, import it into Word, then auto generate a several pages long index, like it is common in book.
The issue is most keywords will have over a hundred occurrences, so a hundred page numbers listed.
Is this acceptable or desirable in a book?
Or should I manually go through my list of keywords, and find the actual explanation paragraph in the book, mark that location for each word, and generate an index with each keyword having only one page number?

[steiconi]

Hundreds of page numbers would make the index fairly worthless. You'd be better off indexing just the useful pages, even if you have to do it by hand.

If you go with the all pages version, see if you can bold the most important page for each.

[buenos]

I found a way in MS Word to manually mark up the index entries, instead of finding all instances. This adds a hidden code into the file that is pnly visible when I enable the special character visibility. It looks like this:
Word word word keyword{XE "keyword"} word word.
This worked well and generated a nice index.
Now my publisher is saying they will convert the word doc into PDF for copyediting and typesetting, that eliminates the index entries. They said I have to make an index in the PDF version.
They suggested a $70 software pdfindexgenerator, but that one seems to only be able to pick up all entries and no manual markups supported. My book is unusual that it introduces ~400 phrases, and each has 10...100 occurrences. Basically, to be able to learn this topic, a massive library of words has to be learned and used. In most books the keyword is used once when it is explained, concepts don't build on other concepts.

So, anyone knows a solution to do manual index entry markup in PDF documents?

[harry chickpea]

Why not just make your index in Word, save the index page as plain text, tack it on to the end of the document, then convert the whole shebang to a PDF? If the publisher wants to make changes in editing only in PDF, it is upon them and the editor there, not you, to update the index as needed. Don't accept BS additional work loaded on you because an editor doesn't like Word.