The order in which you enter the subarea rainfall in the storm file is the calculation order which you can get using the RORB GE.
The easiest way to get the calculation order in terms of subareas is to go to “Data Tables” window under the View tab. When the Data Tables window pops up, you should see two data tables, one for the reaches and one for the subareas. On the bottom right corner you will also see options for list order. Select “Same as RORB calc” and this will reorder the tables in terms of calculation order. This will be the order in which you specify the rainfall depths in your storm file.
The calculation order link you mentioned only shows the control codes in calculation order, so this does not give you enough information for the storm file rainfall depths.