My test show that using the snippet you provided will allow us to update the DirectPct column correctly. The test will displayed the updated DirectPct value correctly in the WebGrid. The test is already using the latest WebGrid 7 build and WebUI Framework 3, build 402 and build 752

Does the update you meant in your post is the update process to the database?

No it's an unbound column. since the Standard Hours and the Direct Hours are stored in the database, there is no need to store the percentage. I just need the calculation change to appear in another column after any changes to the other two fields. I assume I will need to have the same calc for the initialization of the grid.

Are there any settings that need to be set on the grid or column property in order for unbound columns to appear? Do I need to switch from server side binding to client side binding?

In my test, the column must be a bound column in order to set the text correctly. A workaround for your scenario would be modify the select query to include the Percentage Hours, for example

SELECT ID, StandardHours, DirectHours, '' AS PercentageHours
FROM Hours

Initially you could use the InitializeRow server side event in order to fill the percentage hours cell.

Attached is the demonstration of the workaround.