Introduce some further caching for performance gains
Before:
[I 210806 15:33:07 web:2250] 200 POST /calculator/report (::1) 3057.90ms
[I 210806 15:33:34 web:2250] 200 POST /calculator/report (::1) 1695.93ms
After:
[I 210806 15:33:50 web:2250] 200 POST /calculator/report (::1) 2452.51ms
[I 210806 15:33:52 web:2250] 200 POST /calculator/report (::1) 993.42ms