My advice is to get an idea for yourself based on your times compared to Chapmans book, Parks signs or recommendations, and the Abels book.
I will say that I have always found the Abels times way too underdone, that is from memory I always need more time.
Once you have a feel for what the books say compared to how you go on some walks, you will get a better idea on times that you can expect to be able to do a summit in.
Stuart's post is good.
Where he said
depends on your experience / fitness / familiarity with this type of terrain etc
Etc can include so many other things, not least of which is weather (as he covered later in his post).
So, in short, times vary greatly between people. As Chapman says in the notes in (at least) one of his books, it is one area he gets most criticism from on his books. If you get the chance, find that section in his book and have a read - he covers it well.
Happy trails!