On chart, show the date an opportunity was signed/won, but display the most recently updated value

[fagerca7]

Hi everyone,
I have a snapshot of opportunity data taken on the first of each month.  I would like a chart to show the revenue from opportunities signed in each snapshot month (Opportunity Signed Date = Snapshot Date), but display the revenue value of the most recent snapshot, since data can be updated/changed.  The reason I need this is shown in the graph below.  You notice the large spike in 2019-April.  There was an opportunity that was signed in April, but the revenue was not entered correctly (it should have only been .6M).  It has since been corrected, so I would need that peak in 2019-April to show what current revenue value is (which would be the most recent (max) snapshot date, the this case 2019-Dec).

This is how I get the chart below:
sum({$<Status={'Signed'},DateCheck={'1'}>}[Revenue])

(DateCheck = 1 says that the Signed Date = SnapShot Date)

Any ideas how to have the revenue of December show for each Signed Opportunity by SnapShot Month?  I'm stuck!
Thank you in advance!