SQL Server 2012 :: Running Sum With Reset Option And BULK Update

I have come up with an issue where I want to update data in a table using bulk/SET update to get the result shown in below code with output in column titled "Arrear Amt".

Please use this test data.

CREATE TABLE ##vOD_Calc
(
Seq_No INT ,
Contract_id INT ,
Rental_id INT ,
Actual_OD INT ,
Logic_OD INT ,
Due_dte DATETIME ,

[Code] .....

Logic required is that once the sum of column [ArrearAmt] of current row and all previous rows becomes greater than $100 then column [ChArrrearAmt] should show that summed up value and in else case the column [ChArrrearAmt] should show the same value as that of column [ArrearAmt].

Once the column [ChArrrearAmt] reaches the threshold of $100 then the same cycle should start again i.e. in above example rental#1 had $37.17 < $100 then rental#1 + rental#2 is also < $100 and at rental#3 sum of rental#1, rental#2 and rental#3 becomes $111.51 which is greater than $100 so its updated in column [CHArrrearAmt]. The same cycle start overs from rental#4 onwards however the summation of [ArrearAmt] will now begin after rental#4 onwards and not from the starting.

Below is the loop based SQL script which handles the above situation, however in BULK its a total deterioration of performance if thousands of rows are to be processed i.e. with a contract having multiple rentals.

The case here is that I have to use the result of previously updated column value of [ChArrrearAmt] to take decision for the next row, however with BULK update since the row is not yet updated with latest amount therefore the decision on next row is also giving wrong result.

This is the code with which I have achieved to update the column 'chArrear Amount', however its a loop based solution and performance killer.

INSERT INTO ##vOD_Calc_loop
( Rows_count ,
contract_id
)
SELECT COUNT(*) ,
T.Contract_id
FROM ##vOD_Calc T
GROUP BY T.Contract_id

[Code] ....