Long Service Leave Accrual - adjusting calculation basis

Hi,

Nearly two years ago, (22 months) I had a problem with entitlment accruals doubling up & had to make adjustments manually.

I can't remember why, but it seems I've changed the calulation basis for Long Service Leave to "User Entered Amount per Pay Period" at that time.  I didn't realize that had happened and did not enter LSL for any staff.  

I'm assuming I need to work out the missing accruals and adjust the balances.  I haven't done that they but that's my plan.  I then want to change the "Calculation Basis" (Payroll > Payroll Categories > Entitlements > Long Service Leave Accrual), back to "Equals (1.6667%) Percent of (Gross Hours) so the accural can happen automatically.

However, I get the message that that all balances will be cleared.  (see screenshot) Do I just take a note of the balances before doing this,  add them to the missing accrual amounts, and then enter that as the balance?

Could anyone help me with this? (My accountant & staff are all away for a week team building otherwise I would call them).

Kathy