Create Pivot table calculation based on value fields

[akemiann]

I have two value fields in my pivot table. (1) Count of IP - showing the number of hosts out of compliance. (2) Max of Category Host Count - showing the total number of systems affected by a specific technology. I want to have a third field dividing field 1 by field 2 so I can show the percentage of hosts out of compliance. I tried using calculated field and calculated item, but I'm not able to use the pivot table generated fields.