I think that the Post Editing should be not included in the 5 minute sanction. Also, I think you should be able to do like 3 posts per five minutes, still mostly stopping spam and still letting people help each-other and figure their problems out.
Also, if someone really wanted to spam they could get around it. I have used an Arduino Leonardo and Due and with some complex mouse moving and keyboard writing code, along with a delay, I could plug my Arduino in for the night and have it repeat a message every five minutes, effectually getting around the spam blocker.