In the spreadsheet there are a few refinements that could be changed in the spreadsheet including the graph, but then these are also little minor refinements that can be changed to make this spreadsheet more potentially better.
First off all the graph could have been changed or even a new graph could be added in on the spreadsheet. Maybe some people can’t see the difference in a bar graph or can’t tell what the information can tell, so maybe another graph could be added like a pie chart or a line graph. This way people can tell which coach is better in price. Also the graph could have the number of coaches needed and how many coaches are available at that time of the day.
Finally the graph can also have the details of the coaches, so when the user decides on which coach to use they can contact them and confirm their details.
So over all the spreadsheet has many benefits than potential refinements that need doing, but on the over hand the refinements are not major errors on the spreadsheet.