is_last_record =
VAR curProj = data[Номер проекта]
VAR curInd = data[Индекс (№записи)]
VAR lastInd =
    MAXX ( FILTER ( data; data[Номер проекта] = curProj ); data[Индекс (№записи)] )
VAR result = curInd = lastInd
RETURN
    result

meas_1:=CALCULATE ( SUM ( data[Значение] ); data[is_last] )

meas_2:=
SUMX (
    VALUES ( data[Номер проекта] );
    CALCULATE (
        SUM ( data[Значение] );
        LASTNONBLANK ( data[Индекс (№записи)]; COUNTROWS ( data ) )
    )
)

let
  data = Table.Repeat ( #table ( { "clmn_1", "clmn_2", "clmn_3", "clmn_4", "value" }, { { "aaaaa", "bbbbb", "ccccc", "ddddd", 5 } } ), 100000 ),
  recs = List.Buffer ( Table.ToRecords ( data ) ),
  gen = List.Generate (
    () => [ k = 0, cumm_s = recs{k}[value] ],
    ( x ) => x[k] < List.Count ( recs ),
    ( x ) => [ k = x[k] + 1, cumm_s = x[cumm_s] + recs{k}[value] ],
    ( x ) => Record.AddField ( recs{x[k]}, "cumm_value", x[cumm_s] )
  ),
  result = Table.FromRecords ( gen )
in
  result

Длительность = 'Таблица1'[Дата конца] - 'Таблица1'[Дата начала] 

Мера = 
VAR val =
    MEDIAN ( 'Таблица1'[Длительность] )
VAR d =
    TRUNC ( val )
VAR hhmm =
    FORMAT ( val - d, "hh:mm" )
VAR result = d & " " & hhmm
RETURN
    result

let
  data    = #table ( { "product", "value" }, { { "a", 5 }, { "b", 10 } } ),
  typed   = Table.TransformColumnTypes ( data, { { "value", type number } } ),
  addClmn = Table.AddColumn ( typed, "value_sum", each List.Sum ( typed[value] ), type number )
in
  addClmn

[
  data    = #table ( { "product", "value" }, { { "a", 5 }, { "b", 10 } } ),
  typed   = Table.TransformColumnTypes ( data, { { "value", type number } } ),
  addClmn = Table.AddColumn ( typed, "value_sum", each List.Sum ( typed[value] ), type number )
][addClmn]

let
  data    = #table ( { "product", "value" }, { { "a", 5 }, { "b", 10 } } ),
  typed   = Table.Buffer ( Table.TransformColumnTypes ( data, { { "value", type number } } ) ),
  addClmn = Table.AddColumn ( typed, "value_sum", each List.Sum ( typed[value] ), type number )
in
  addClmn

let
  data    = #table ( { "product", "value" }, { { "a", 5 }, { "b", 10 } } ), 
  typed   = Table.TransformColumnTypes ( data, { { "value", type number } } ), 
  val_sum = List.Sum ( typed[value] ),
  addClmn = Table.AddColumn ( typed, "value_sum", each val_sum, type number )
in
  addClmn

  #"Добавлен пользовательский объект" = Table.AddColumn (
    #"Измененный тип", 
    "Пользовательский", 
    each [ new_date = Date.AddMonths ( [Дата приема], 3 ), result = Date.AddDays ( new_date, Date.Day ( [Дата приема] ) - Date.Day ( new_date ) ) ][
      result
    ], 
    type date
  )