I doubt your agent has gotten actual numbers from the seller's agent. Remember that your agent is YOUR AGENT and would have a fiduciary duty that probably involves disclosing that number to you if he knows it. Realtors in your area tend to work with one another a lot, so make sure they're not valuing that relationship better than your principal-agent contract.
If he's had that conversation but isn't telling you the exact details, find a new agent. It's hard to find one that's trustworthy because their commission depends on the sale price. Therefore, who are they really working for? Find one that really works for you, and stick with them, because they will be few and far between.
FWIW, my agent, who I do trust, thought that our property would fall at 10k more than we actually paid for it. That's a pretty close estimate, but if you don't want to jump from 200 to 215, you can try smaller increments. At some point it isn't worth haggling over 10k, but when 10k is 5% of the purchase price, it's still a factor. Still, I went ahead with a smaller bid because the property had been 8 mos on the market, and it ended up taking.
Having a buyers agent is not an excuse to not do 95% of the research yourself. Use the agent to handle negotiations with the other party, paperwork, and their industry knowledge when you need to fall back on it. Everything else, including area values, recent comps, etc should fall on you.