In case you received a notice u/s 143(1) saying there exist an arithmetical error in you Return probably stating that ‘In Schedule BP, Sl. No. D. Income chargeable under the head PGBP(A38+B43+C49) and the sum of amounts entered in A38+B43+C49 are inconsistent‘, you must have tried adding those figures again to just to find that there exist no such arithmetical error. Since returns are prepared by software, chances of an adding mistake is very slim. This article describes another possible reason for this error.
This reason I found out is applicable only for such assessee where Tax Audit report(3CD) is also filed. So read ahead only if you have filed 3CD for that year.
The department has a step by step automated procedure for discovering errors in the ITR and by analysing few returns, it was found that:
In order to ensure this is the case, try adding the disallowance figure from 3CD and check whether is that the amount computed by Department to be the expected total at Sl. No. D in ITR. So to conclude, there might not be any arithmetical error but difference in amounts with 3CD.
The above mentioned points are only my own opinion and not a final conclusion. Hope this article finds use to you and do let know any mistakes in the comments.