The Write Profile menu item invokes the same dialog as Monitor in the Computation menu for time dependent computation: The Monitor/Write Profile dialog. This dialog has three tabs for writing points, polylines, and the entire file.
However, there are two dialog elements which are available only when you access the dialog via the Monitor menu item in the Computation menu:
The field Save every ... time step at the bottom of points and polylines tabs
The Entire file tab
The reason is that both elements require time-dependent computation.
This export dialog is the most complex one because you have three tabs for defining different data ranges. The data are saved to ASCII files with the extension *.mon and a specification for the data range.