While loop became slower after some recursions in sql server - sql

Question

I have a stored procedure which uses a while loop to iterate to each record
and do some calculations. The stored procedure has the following logic:
Inserts some records from old_table to new_table for a specific range
(7.8 million records) . insert took 4 minutes.
Then it copies records which have amount > 100 into a temp table
(37 000 records).
create clustered index on the id column of temp table.
start the while loop to iterate to each id column in temp table (total 37 000 records).
for each iteration a stored procedure is called inside the while loop.
The Sp works fine (faster) Up to 5 000 records (it completes in 5 mins)
but after 5 000 there is a delay in processing records. The delay occurs after processing each 100 records. Is there any reason for this delay?
sample structure of the stored procedure:
use my_db
go
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
IF OBJECT_ID('[dbo].[usp_datacopy]') IS NULL -- Check if SP Exists
EXEC('CREATE PROCEDURE [dbo].[usp_datacopy] AS SET NOCOUNT ON;') -- Create dummy/empty SP
GO
ALTER PROCEDURE [dbo].[usp_datacopy]
#Startdate datetime,
#Enddate datetime,
#Percent int
AS
BEGIN
SET NOCOUNT ON;
BEGIN TRY
BEGIN TRAN
DECLARE #PerVal NUMERIC(10,2) = #percent /100.00,--Get the percent value for input.
#wkstartdate DateTime,
#wkenddate Datetime,
#OfficeID int,
#id int = 1,
#spcount int ,
#rdate datetime,
IF OBJECT_ID ('TEMPDB..#temptable') IS NOT NULL
DROP TABLE #temptable
INSERT INTO [dbo].[new_table]
( TimeID, OfficeID, dateval, rHour, Complexity,RowCountval)
SELECT TimeID + 364, OfficeID,dateadd(dd,364,dateval),rHour, Complexity , RowCountval,
FROM [dbo].[old_table] WITH (NOLOCK)
WHERE dateval BETWEEN #Startdate AND #Enddate
--select Day records with value > 100
SELECT ROW_NUMBER() over(order by timeid) id,TimeID, OfficeID, dateval, rHour, Complexity,RowCountval
INTO #temptable
FROM [dbo].[new_table] WITH (NOLOCK)
WHERE RDATE BETWEEN #wkstartdate AND #wkenddate
AND RowCountval > 100
CREATE CLUSTERED INDEX id_index on #temptable (id)
SELECT #spcount = COUNT (1) from #temptable
WHILE #id <= #spcount --37000 records
BEGIN
SELECT #OfficeID = officeid FROM #temptable WHERE id = #id
SELECT #rdate = dateval FROM #temptable WHERE id = #id
EXEC CalcPercentforEachRecord #rdate, #OfficeID, #PerVal
PRINT #ID
SELECT #id = #id + 1
SELECT #OfficeID = NULL
SELECT #rdate = NULL
END
IF ##ERROR = 0
BEGIN
COMMIT TRAN;
END
END TRY
BEGIN CATCH
SELECT ##ERROR AS ERROR,ERROR_MESSAGE() AS ErrorMessage,ERROR_LINE() AS ErrorLineNo
ROLLBACK TRAN;
END CATCH
SET NOCOUNT OFF;
END