Offersubmission.com for REO Property Offers - Is this a Scam?

[Patrick M.]

So I made an offer on a REO property being represented by a realtor that I found through Zillow. He told me the bank that owned the property, provided a contract template, and I filled it out and provided an offer. Today, AFTER the offer, he tells me that he submitted it to the bank via offersubmission.com and that there will be a $300 fee to the Buyer (me) at closing for doing so.

This seems insane to me. He knows who the bank is, but he has to put my emailed PDF offer in a special website to send it in so that I get charged $300?

Does anybody have any experience with this and can tell me what is going on? Thanks!