how long does "fixing" a document take

[Carrie Baker]

I am sure that this is a question where the answer is "it depends",
but I would like to get a sort of estimate to see if I am in the
correct direction.
A programmer for whom English is not their mother tongue, wrote an
internal document explaining to sales staff how to demonstrate a
complex application. (it is not a user guide, but more in the
application note direction).
The document is around 31 pages long and covers over 20 screens some
of which are divided into additional panes etc.
I was asked to edit this.
Apart from editing, I am running the data he used, with the
application to make sure no steps are missed out.

All in all, I am fixing the English, adding formatting, (headings,
numbers whatever is required), and making sure the whole thing makes
sense and works.

This seems to be taking me a long time. How long do you think
something like this should take??
-- 
Carrie Baker
carriebak at gmail.com