Well, when you're just getting this random information off the internet, it's hard to know what to believe sometimes.
The chemical service you're considering might very well work for you. I think the key is just to have a good stylist who knows how to apply the product right without overlapping the chemicals.
Chemical treatments in general make your hair more fragile. So, just treat your hair gently.
This article is talking about perms, but the chemical is the same:
Want Curls With Less Damage? Try This New Way To Perm!: Beyond the Beauty Pages: Beyond the Beauty Pages: Self.com
Here is a positive viewpoint from a stylist:
Keratin hair straightening is flat-out fabulous for the formerl... - Topix
Here is the whole process step by step:
Pravana's Keratin Fusion: Before, During and After Photos
If you have any concerns, maybe you should discuss it with your stylist. Hopefully, there is someone who posts on this board can really advise you.