Why would you only allow +/-5 on the timestamp? The protocol allows a much larger range than that. In most cases, you should be able to get somewhere close to between -3300 and +7200.
Was just to remain covert - any big timestamp diffs would be obvious.
You have big timestamp diffs all the time. Just look at how many non-chronological timestamps there are (4.6% of blocks from 2013 to 5/2015, from post #150 of old thread)