Using historical dates to calculate system status at intervals in the past

I did come up with a solution, but more complex than I hoped (though still wonder if there is a simpler solution).

I had this table called DateHalfYear to start with - a simplified date-type table with dates each six months for a few years:

I then created a new table called PagesWithDates in Power Query, that included a row for each date in the above table for each page record (total rows in new table = number dates from above table x total page records):

let
    Source = DateHalfYearDim,
    RemoveCols = Table.SelectColumns(Source,{"DateKey"}),
    AddPagesFactAsColumn = Table.AddColumn(RemoveCols, "Pages", each Pages),
    ExpandPages = Table.ExpandTableColumn(AddPagesAsColumn, "Pages", {"PageKey", "SiteKey"}, {"PageKey", "SiteKey"}),
    ChangeTypes = Table.TransformColumnTypes(ExpandPages,{{"PageKey", Int64.Type}, {"SiteKey", Int64.Type}})
in
    ChangeTypes

I then hooked up the new PagesWithDates fact table to the relevant dimension tables:

And added a calculated column to PagesWithDates table to work out the months since last review for each page record at each historical date:

Months since last review = 
VAR dateToWorkFrom = RELATED(DateHalfYear[Date])

VAR pageKey = PagesWithDates[PageKey]
VAR lastReviewedDate =      
    CALCULATE(
        MAX(Reviews[DateReviewCompleted]),
        FILTER(Reviews, 
            Reviews[PageKey] = pageKey &&  
            Reviews[DateReviewCompleted] < dateToWorkFrom
        )
    )

VAR monthsSinceLastReview = IF(NOT ISBLANK(lastReviewedDate), DATEDIFF(lastReviewedDate, dateToWorkFrom, MONTH))

RETURN
    monthsSinceLastReview

Then created a measure to count the number of pages more than 3 years since last reviewed

Number pages greater than 3 years since reviewed = 
COUNTROWS(
    FILTER(
        PagesWithDates,
        PagesWithDates[Months since last review] > 36
    )
)

(I guess a more complex measure could be used to eliminate the need for a calculated column, but I found it simpler to think of it this way)

Lastly, I created a matrix from:

• Rows: Site[Site name]
• Columns: DateHalfYear[Year] and DateHalfYear[Month name short]
• Values: [Number pages greater than 3 years since reviewed]

This has produced a result that is sufficiently accurate for my purposes and that shows the trends over time with respect to the number of pages that were 'overdue' for review (i.e. more than 3 years since last review) at each historical date, with dates at intervals of six months.

Any comments on whether such a complex solution was needed, or refinements to the above solution are appreciated.