Determine frequency of a serie and amount of data missing

It would seem to me that there will need to be a list of dates for which bills are expected such as modeled in columns V and Z.
V4:V31 are populated using: =IF(V2="","",IF(EDATE(V2,1)< TODAY(),EDATE(V2,1),""))
Z4:Z31 are populated using: =IF(Z2="","",IF(DATE(YEAR(Z2),MONTH(Z2)+3,1)< TODAY(),DATE(YEAR(Z2),MONTH(Z2)+3,1),""))
Note that in both columns the cell in row 3 is manually filled.
In each case the next two columns display the quantity and price for that month.
W3:X31 are populated using: =IF($V3="","",IFERROR(1/(1/SUMIFS(Tableau1[Quantity],Tableau1[[Energy]:[Energy]],$V$2,Tableau1[[Date]:[Date]],$V3)),"Missing"))
AA3:AB31 are populated using: =IF($V3="","",IFERROR(1/(1/SUMIFS(Tableau1[Quantity],Tableau1[[Energy]:[Energy]],$V$2,Tableau1[[Date]:[Date]],$V3)),"Missing"))
The counts of the missing quantities and prices are displayed in row 1 using: =COUNTIFS(W3:W31,"Missing")
Let us know if you have any questions.

Hi JeteMc,

Thx for your contribution. I don't fully understand the 1/SUMIFS part, but I eventually will. Some sort of control mechanism I've seen around, and I will get to it one day.

As for your way of solving, that would work. I could have a separate table, though I wouldn't input either Price or Energy, but just count the missing data and sum it up in a Pivot Table so that's it's updated depending of the selection I make (my graphs are all coming from Pivot Table).

My remaining problem is that I can't input the expected date it's coming. Too many different contracts to check. What isn't displayed in my sample for sake of simplification, is that all this information is location dependent and I have lots of different locations in my full set of data.
I have to deduce the frequency of a given set of data and count the possibly missing sets.

What I'm doing now is to :
- check the first date entered in one serie
- check today's date
- count the number of month in between those two dates
- count the number of values between those two dates
- Compute and display the number of missing values according to the result (calculation takes into consideration that periodicity could be monthly or bi-monthly, sometimes every semester)
- calculate and display the percentage of accuracy of the serie.

That works without entering any other information into my tables. But the more data my pivot table contains, the more nonesense this method output, because it always end up being more accurate (both in quantity and percentage) if I group everything, as this way of proceeding always finds (multiple) values monthly in both fields.

I'm beginning to think that my lack of statistical skills (in math in general and excel in particular) is what's limiting me
I'll keep on improving those.