Ah, the good old over-quoting trick to ensure a vendor signs up the agent! It is so important to read and make sure all parts of the selling agency agreement, ie. commission, price estimate, etc, have been filled out and that you agree with them before signing it.
On the front page, it will have a section where the agent has to give their best estimate at what they truly believe your property will sell for - they are then obligated to achieve this. I once got an agent out to give a quote on a house I was selling - when it came time to discuss what he thought it would sell for, he 'didn't want to write any price down on the agreement' despite happily and confidently TELLING us verbally that our property would sell for a sum that seemed too high. He wanted us to sign up and 'leave that part blank'. Um... no. He was a shonk... and I told him so
So, what 'price estimate' has this agent put on the front page of your selling agency agreement? And, is it anywhere near what you are being offered?