Hi Tim
I'm not 100 percent sure, but I think with Ebay and "make an offer" option, you only get 2 chances to give your offer per listing cycle. Once the offers either expire or are rejected, then that's it... no more offers accepted by you from the seller.
I think they do this so that when a seller has an auto accept on their item, you cant start low, and increase a penny every time till you hit their "willing to sell point"
This way, your offer may be higher than what they would have let it go for.
Again, not 100 sure, but I'm pretty sure lol.