We have context sensitive help links from our software to our help site. On William's site, it recommends to have the CSH URL from the software in the form www.helpsite.com/index.htm?rhcsh=1&rhmapno=10. However, I've found that www.helpsite.com/topic.htm?rhcsh=1&rhmapno=10 also works (replacing index.htm with topic.htm). Does anyone know of a reason NOT to use topic.htm in the URL? This method looks better to me as it reduces the number of redirects a user sees before the help topic is displayed, but maybe I'm missing something.
I found recently that if I clicked a topic in the TOC, the link in the address bar was somewhat different to the link if you followed it in File Explorer. Then if I used the link that was in the browser after I had applied an update to the help, it wasn't bring up the new stuff. Bizarre and illogical but that's the way it was.
I know your question is a different scenario but because of that blip, do test carefully if you do it any way other than as recommended.