Microsoft Word 2013 and 365 (2016) Grammar vs Grammar and Style

Hello All;

  OK, I have been writing a book for well, over a year now, off and on. And I also use Word on a daily basis, to make sure that the articles I am writing, or spelled and structured correctly.
The question here is pertaining to the
2013 = Grammar and Style
2016 (365) = Grammar.

Example
(365) = as I did not wont to wake her.
(2013) = as I did not won't to wake her.
(or) = as I did not want to wake her.

When I am using 2016, I can pretty much write it any way I want, and it comes out OK, with simple to correct errors or warning.
However, in 2013 an below, set to Grammar and Style
I find a few more issues, and at times, very difficult to correct.
What may sound right to me, and to my Mother (I read everything to hear for approval (She is an avid reader))
Brought into 2013, shows typically, more of the red or blue lines.

So.
My question is this.
Is the removal or the Grammar and Style in 365... a good or bad thing?
And should I just use 2016, and continue writing the way I am, and publish my work when it is done?
Should I fall back and use 2013, for the over abundance and error checking with, Grammar and Style?
Or, is there a BETTER program out there, designed for writers?

Thank you in advance.
Carrzkiss