NEST expects submissions to be made per Earnings Period (regardless of being paid in arrears), which is confirmed as accepted by TPR.
However, the only way to amend these date is using the "adjust dates" functionality, which does not work for monthly payroll processing, especially with the hope to automate the pension submissions through API.
The idea to make this a permanent reconfiguration of your processing has been rejected, so I hope you are able to implement this as a work-around for your users.