My experience is that you can get odd merges but it doesn't matter. I often get something like BISONRAV FIRSTNAMESECONDNAMR and Master BR who has a lot of names, English and Chinese, sometimes gets initials after the first name. As long as it's demonstrably close to the name in the password it's fine, and I've certainly travelled on BISONRAV FIRSTNAME though I did have one picky agent in Indonesia I think so I tend to include everything.

Where you do need to be accurate is API, but for check in and travel it's less of an issue I think.