Also it's been my experience that a lot of trade companies charge the customer the retail price and keep the profit from them being able to purchase at a lower trade discounted rate. So you may not have saved much on materials Regs.
total labour = 7 days = 56 hours = $2240 (@ $40/hr)
I would expect pro to do it in probably half the time. Also larger pavers could mean a time saving, as less pavers to cut, and less tiles to lay.
the pro's would definitely lay the pavers and prep the base course faster, but I seriously doubt that they could have cut up the lava rock faster than the 3 days :O .... although they might have employed a $20/hr labourer which would have been a cheaper option.
here is a sample of the lava rock fun to be had....
P.s. there was no room to get an excavator in here, that would have been the best option by far!