First of all, thank you very much for your support.
I think you have aready understand everithing: your description seems to fit.
However, the main requirement to satisfy is to show two data series that must be aggregated with SUM() by hour/day/month/year.
Let's call the first data serie SUM(N), having N all the samples.
The second one, having M as samples, must be calculated by K*( SUM(N) / SUM(M) ), so by using the N samples already used in the other serie.
Hope is clear enaugh...
Thank you again!
Luca