Data Conversion Issue

My below code works fine, where i get the colum(Payment1 and Payment2) values from [TEMP_PAYMENT_TABLE] to MY_TABLE.

When i add the add third colum(Payment_Due) that does substract operation(Column1 "MINUS" Colum2)
I get the below error

Conversion failed when converting the nvarchar value '0.0000' to data type int.

Here the are few null values also in colum 1 and colum2

WITH mycte AS (
SELECT [PROCESS]
,TRY_CAST([LOAD_XML] AS XML) bond
FROM [TEMP_PAYMENT_TABLE]
)
INSERT INTO [dbo].[MY_TABLE]
(,[PAYMENT_VALUE1]
,[PAYMENT_VALUE2]
--,[PAYMENT_DUE]
SELECT
S.a.value('(Compamy/Payment1/text())[1]', 'nvarchar(255)') Payment1
,S.a.value('(Compamy/Payment2/text())[1]', 'nvarchar(255)') Payment2
--,S.a.value('(Compamy/Payment1/text())[1]', 'nvarchar(255)')-S.a.value('(Compamy/Payment2/text())[1]', 'nvarchar(255)')
FROM mycte t
CROSS APPLY t.Payment_xmlload.nodes('/.') S(a)
--select * from [dbo].[MY_TABLE]