I don't know if this will solve the problem for you. In a PoC I did with this app, all the throughput values were '0'. However, there are some other issues with the dashboard which may be solved by:
-Clicking on the "Edit" button for the dashboard
-Click on the pencil (Edit input) for the "VNX block Array"
-Scroll down to "Search string" The search string defines index=vnx, change this to `vnx_index` (include the back-ticks!)
-Click the pen (Format visualisation) in the "Heat Map - LUN Throughput (IOPs)" panel where you may need to change the number of categories which is set to 10, you may need to set it to 100.