I can't install OD to a specific directory, why?

System

I was forced to uninstall OD and re-install it in order to fix a problem we we're encountering. When we upgraded from 5.5 to 6 it allowed OD to be installed into the prior directory named od-home. Now, however, when I come to re-install OD it insists on intsalling to a directory named OpenDeployNG. Why can I not specify where I want it installed? This is going to cause even more work/problems........