If an employee has a Default Pay with an accumulator balance (this article explains how to set these up) the current balance will now show on payslips. Note that it is only shown after the pay is finalised since this is the point at which the balances are calculated. It is also only shown for pays finalised after 19 September 2017.
This history of balances is now available in the Report Centre. Use the Pay Detail table, filtered to the pay code of interest. Rather than using Sum as the Function you're best to use Min (or Max) so that if there are multiple pays for an employee on the same day, the lowest (or highest) balance will show, rather than adding the balances together.