Interest rate change can be applied multiple times if lease is paid In Arrears
Change to Interest rate can be applied in column O if rate is implicit or Column Q.
System will prefer Implicit rate if it has been entered.

In example above it takes IBR as Implicit rate is not entered in cell A7. In Column Q (all fields in yellow can be safely modified) numbers are changed to showcase increase in IBR from April until July.
This is also reflected in Re-measurement of lease: