How to sum chain values from N-number cells?

How about a generalized Lambda to handle this task?

I've included a workbook with GroupbyBinλ.  All you would need to do is move your data to this workbook and run the function. I've included a few examples to get started.

Edit: it looks like this forum is still not accepting attachments. Here is the workbook:
GroupbyBinλ Demo.xlsx

For those interested, here's the function:

// Author: Patrick H.
// Date:   11/29/2025

// [Note: part of a larger module to include GroupbyDateλ, Histogramλ, Streakλ,
//        Modeλ, and more!]


//--- GroupbyBinλ ---
//
// Description:
//   Aggregate one or more value arrays into fixed-width bins
//   derived from a numeric field.
//
// Parameters:
//   array        - Numeric array (1D) used to define bin boundaries.
//   values       - Array(s) to be aggregated (1D or 2D).
//   bin_width    - Positive integer specifying bin width (≥1).
//   function     - ETA-compatible function or single-parameter LAMBDA.
//
// Optional Parameters:
//   [field_header] - TRUE if input arrays include headers.
//   [chart_prep]   - TRUE to return a concise chart-ready layout
//                    (bin start/end joined into one column).
//
// Notes:
//   • If bin_width = 1, behaves like GROUPBY (no binning).
//   • If bin_width ≥ (max-min), collapses to a single bin.
//   • Chart mode produces {"Bin","Aggregate"} output for plotting.


GroupbyBinλ=
LAMBDA(
    array,values,bin_width,function,[field_header],[chart_prep],
LET(
    //Dimensions
    i, ROWS(array),     j,  COLUMNS(array),           
    i_,ROWS(values),    j_, COLUMNS(values),

    //Header check
    Headers?,           NOT(ISOMITTED(field_header)),

    //Halting scenarios
    Is2D?,              AND(i>1,j>1),
    ShapeMismatch?,     i<>i_,
    InvalidBin?,        OR(ISTEXT(bin_width),bin_width<1),
    InvalidFn?,         ISERROR(OR(BYROW(SEQUENCE(3,3,1,0),function))),
    NonNumeric?,        NOT(AND(ISNUMBER(IF(Headers?,DROP(array,1),array)))),     

//Logic gate

IF(Is2D?,               "#1D-ARRAY!",

IF(ShapeMismatch?,      "#DIMENSIONS!",

IF(NonNumeric?,          #NUM!,

IF(InvalidBin?,         "#BIN-WIDTH!",

IF(InvalidFn?,          "#FUNCTION!",

//Proceed

LET(    

    NoChart?,               ISOMITTED(chart_prep),
    arr,                    IF(Headers?,DROP(array,1),array),
    val,                    IF(Headers?,DROP(values,1),values),

    //Assign headers
    row_header,             HSTACK("Bin Start "&IF(Headers?,TAKE(array,1),"")&" Value","Bin End"),
    val_header,             EXPAND(IF(Headers?,TAKE(values,1),"Total"),,j_,""),
    header,                 HSTACK(row_header,val_header),

    //Bin arrays
    min,                    MIN(arr),
    start,                  FLOOR(min,bin_width),

    max,                    MAX(arr),
    end,                    CEILING(max,bin_width),
    k,                      (end-start)/bin_width,
    
    bin,                    SEQUENCE(k+1,,start,bin_width),
    bin_start,              DROP(bin,-1),
    bin_end,                DROP(bin,1),

    //Bin assignments
    i,                      XMATCH(arr,bin_start,-1),
    row_start,              INDEX(bin_start,i),
    row_end,                INDEX(bin_end,i),
    row_fields,             HSTACK(row_start,row_end),

    //Aggregation
    agg,                    GROUPBY(row_fields,val,function,,0),

    //Chart prep
    a,                      CHOOSECOLS(agg,1)&" - <"&CHOOSECOLS(agg,2),
    b,                      DROP(agg,,2),
    chart_labels,           {"Bin","Aggregate"},

    //Return modes
    data,                   VSTACK(header,agg),
    chart,                  VSTACK(chart_labels,HSTACK(a,b)),

    delivery,               IF(NoChart?,data,chart),
    delivery
))))))));