We do the same and have had no issues.
findlotsize.com is good for measuring. I can't imagine showing up and running a wheel on every estimate we do. We would never get any work done. If it's a huge property I will spot it on lotsize.com just to get an accurate measurement but for most residentials, you can walk them and know how long it will take. Like someone else already said property size is only part of the information used for an estimate.