AN,
Here is the problem with submitting multiple offers vs accepting them. A seller puts his home on the market and people submit offers. How many come in is not under their control. A buyer submitting legal offers to purchase a property is falsely proposing to buy something. If everyone accepted your offer would you buy them all? Of course not! My point is that you dont need to do this to negotiate the best deal and to the contrary you will be percieved as less than desireable.
Someone evaluating your offer as 1 of 5 will analyze it as a 20% chance of acceptance followed by less than a 50% chance of the you completting the purchase. Thus they are looking at the highly probable outcome of your offer (a less than 10% success rate) as undesireable. If you are going to submit multiple offeres I wouldnt tell them I was doing so, it will hurt more than help.