If you do an Active Form from the cube viewer and the row dimension does not contain a subset then it will create a hidden sheet in the workbook that contains a list of the elements you had in the rows.
Your TM1RptRow formula will then reference this hidden sheet with a formula similar to ({AR}01'!$B$17:$B$22)
These references to hidden objects perform slower on tm1web then references to subsets or mdx. For performance I would recommend replacing these hard coded references by changing the TM1RptRow formula to use the subset or mdx parameters and deleting the hidden sheet within the workbook
