Integral with timeWeightedAvg and stepped line

[thkoinje]

I would need to calculate the stepped integrated average of a timerange for compressing data.
In the picture there are several measurements shown as red points.
The orange line I guess is the line used to calculate the timeWeightedAverage of the timerange between 0 and 10.
The green line is the needed line for the calculation.

Calculation:

Timeinterval	Value orange	Value green
0-1	1,25	2
1-2	2	1
2-3	2	1
3-4	2,5	3
4-5	3,5	2
5-6	3,5	2
6-7	3,5	2
7-8	4,375	5
8-9	4,375	5
9-10	4,375	5
Total	31,375	28
Average	3,1375	2,8

Can you please help me to set this up right?
Up to now it is something like:
|> aggregateWindow( every: 1s, fn: (column, tables=<-) => tables |> timeWeightedAvg(unit: 1s), createEmpty: false)

[thkoinje]

Here is another discussion: #24315
I guess it is the same topic.