There is no command equivalent for that part of Render By Attribute unfortunately. I've put making a command equivalent on a to-do list. So you will have to resort to the Python part of the per-frame scripting dialog. I've attached a Python file that goes through currently open molecules and writes out the areaSAS attribute of residues into files named /var/tmp/sasNNN where NNN is 001 for frame 1, 002 for frame 2, etc. You will of course have to have added a surface. You can use the "Insert text file..." button of the per-frame dialog to directly enter the script from the file.

If you know Python, the script is pretty straightforward. The only tricky part is right at the beginning where it calls checkForChanges(). This allows the surface-computation code to immediately notice that the structure coordinates have changed and recompute the surface. Otherwise, the surface-computation code wouldn't get that notification until after the per-frame script had run, so the surface areas we print out would always be off by one frame.