If a domain on Sedo has an asking price instead of just 'offer' and you meet the asking price it is still subject to acceptance from the seller.
Therefore there is nothing stopping the seller waiting out the 7 day timer then bumping up the price.
for example Joe Bloggs lists Domain.com for sale @ $1000 and gets a $1000 offer on the day he lists it. There is nothing stopping him thinking he could get more for the name seeing as someone is willing to pay the asking price so waits for 7 days then ups selling price to $2000.
Therefore there is nothing stopping the seller waiting out the 7 day timer then bumping up the price.
for example Joe Bloggs lists Domain.com for sale @ $1000 and gets a $1000 offer on the day he lists it. There is nothing stopping him thinking he could get more for the name seeing as someone is willing to pay the asking price so waits for 7 days then ups selling price to $2000.