For 1.19 million requests results in about 330 hours. So the net saving in time per month is about 2400 hours. Measurements on the other 18 first level caches are not known yet, but if the order in savings on wait time is the same, the total saving in time expressed in salary is about MECU 6. It is perhaps not realistic to count the total time saved. One must realise that the total time is divided over many clients and many requests.
Every request accounts for a very small part of the total time saved.
For the first level cache UU, the 900 hours time saved should be divided over 750 unique clients, meaning a time saved of 1.2 hours per client per month. Instead of expressing the time saved in total hours and salary it could be better used as a measure for the improvement perceived quality of service by the users. This should be noticed by the clients who use the cache. The use of a caching service could remarkably reduce the load on the origin Web server. Especially for Web servers with very popular pages as these often requested pages are placed on the cache server.