After update Dutch a small shift in tax return reports in the past

I wrote earlier about the tax reports and because of @Hennie (eerst kieken dan kwekken), I solved the problem for my coompany.
My son however had the same issue, but this time, when folowing all the steps Hennie advised I am left with old Tax return reports (2017, 2018, 2019) that show a small shift between 1a (high tariff, 21%) and 5b (tax return mixed 21% , 6%, 9%). The total amount of the tax return is about the same.
Were the old reports for Apple not correct and are now corrected?
Or is is there still something that should be corrected on my side?
After checking revenues taxes and purchase taxes, which are all correct now, I do not know where to start.
The old one back in 2017

The new one with the new tax reports imported over the same period

Any suggestions?

With the information you provided it is hardly possible to discover what happened.
A few remarks::
I assume the old report is the report he printed at the time he did the tax-return in 2017 and the new report is recently printed.
It could be that after he did his tax-return, that he made a booking afterwards in Q1 2017. That could cause the difference.
It is best to analyse all Vat from the beginning up until now and see if the balance as it is per today in Manager is the correct balance due.
I could be of assistance if you don’t know how to do that. In that case let me know by private mail.
Hennie.

@Hennie We will start with checking VAT balance.
There was nothing added or deleted in the postings earlier
as after VAT statement the period was closed.
If needed we will come back to you for help ! Thanks.