Re-using custom rules

I have a question about the usage of the <customN> rule type. Would it be permissible to re-use the same custom rule number if one used exactly the same script in it? That is to say, I have multiple rules that use the same script, but look for different matches on it. Would it be acceptable to re-use <custom1> for all of those rules? I am guessing that it would, because the script would merely be copied into the same file name repeatedly, thus doing no harm... but I thought I would check to see if someone could actually confirm this.