Please remember to post documentation-related requests in the feature suggestions forum. The bug reports forums are for bugs in features.
That said, this is not actually a documentation issue. It looks like a bug in the way the high resolution timer is handled. mIRC creates one high resolution timer that is used by all /timer -h requests. However, it looks like the call to the high resolution timer was failing if it had already been created, causing the second /timer -h to default to an -m timer - which is in fact what will happen anyway if a high resolution timer is not available. This issue has been fixed for the next version.
