Grammar, Usage / Questions regarding some corrections suggested by Microsoft Word [3]

phrases suitable for PhD thesis

Hi there!

I am writing my PhD thesis (in Neuroinformatics). Word corrects me on some phrases I have mentioned below. I think the ones on the left column sound more formal and therefore, more suitable for the purpose of a PhD thesis. On the other hand, the Microsoft Word offers corrections I mentioned on the right column.

Similar to -> like
in order to -> to
main focus -> focus
has to -> must
really helpful -> helpful
at the moment -> now
the final result -> the result

Furthermore, Word sees the following terms as not being present in the English dictionary. However, I have read many papers that included these terms:
ontologies
curation
neuroimage (I can imagine why this one is problematic)

In addition to the above, the other day my supervisor told me it is better for me get help from a copy writer. This came to me as a surprise since I thought my writing is fine despite not being a native English speaker! :) How does my English sound? Should I get help from a copy writer? Because I assume they are expensive; however, I don't want to fail because of some wording or grammar issues! :-O

Personally, I think she did not bother even reading the thesis completely. She probably just looked at the Word corrections and concluded that my English is not good enough(!)... Or maybe right now you cannot even understand what I am saying (?!) :)))

So, please let me know since this is very important to me and I do not have much time left! :-|

PS: Sorry for asking two questions in one! :)