Correcting doubled super

Hello, I am tidying up QB for a new client & who had an issue with Super being included twice as

Employer Super Contribution of 9.5% had been selected in payroll inclusions. I have corrected this for entries moving forward however wondering how I can correct the prior entries from October 2020 till now? 

Can I back date a correction? Considering deleting the pay runs and reentering them correctly as they have not been submitted to ATO yet, nor has super been paid to superfunds (but does need to be very soon) and could just do a balancing payment to employees.  Any advice much appreciated - my previous clients have not had employees so definitely a bit out of my depth with this.

Thank you very much, Fiona