YTD payroll figures different before and after upgrade

Hi my last pay run period end date was 22/1/23 

I've been upgraded since then and wanted to check the YTD figures (gross, PAYG and   Take home) from our employees last payslips to the YTD figures up to 22/1/23 now that the system has been upgraded.

I ran the 'pay item transaction report' with all payroll categories except PAYG and super for 1/7/22 to 22/1/23. They don't match, the gross is less after the upgrade??? 
I also ran the same report for just PAYG and again the $$$ amount is less than the payslip before the upgrade.

we only have two employees and it's less for gross and PAYG YTD for both.

I don't understand why this would be different now and doesn't give me a whole lot of faith that everything else has carried through properly meaning more checks need to be done.

for example, I've commented on another post because I reconciled all accounts at 31/12/22 and now nothing reconciles!

Another issue is that the base rate for both employees is the same in the pay item, however when I ran the pays the base rate is 2cents more per hour for only one of the employees??

So far I've been on the system twice since the upgrade and it's proving to be really frustrating!