I don't think it should be an error for 2 different scripts to both ask for position N in the menu, just like it's not an error for 2 scripts to be loaded to the top script position with /load -rs1
For this feature to work, it very likely needs to have the ability to know what's the current design of the menu. Something like the following being in a menu can change the needed insert position for things beneath it, depending on active conditions:
$iif($1 isop $chan,Label) : command
Something similar to how $script() works, like $menu(nicklist,0) $menu(channel,5)
