Ok, Darin - since you said it's set to 30 seconds, here's my proof..
I answered one PM from one person, went right into a second PM from another, replied immediately, and this is what popped up:
<b> The following errors occurred when this message was submitted:
1. This forum requires that you wait 60 seconds between sending private messages. Please try again in 19 seconds.</b>
This forum requires that you wait 60 seconds between sending private messages. Please try again in 19 seconds. Then it went to 7 seconds next time I tried. freakin worsome.