I tried to find your stories, so I searched by author and didn't find any. However, a few general comments.
Spell checker works fine except that it can't find words that are spelled correctly but are the wrong word, for example except and accept, which and witch, there are many examples. There is no software that can work better than simply knowing grammer and spelling.
An author works with words, just as a carpenter works with wood and tools. It is part of the work of being an author to learn grammer and spelling.
There is also British spelling and American spelling. Centre is British ( I know the Canadians spell that way too, so do Australians.) Either is acceptable, but if you shouldn't mix the two types of spelling. Arse, for example is a
British spelling. American is ass.
Writing is a craft learned through hard work, it isn't just cool ideas, it is making those ideas available to your readers. Proof reading is just a way to make sure that you aren't making a stupid mistake, like writing too instead of to or two.

Meanmaster