You could create a Wage Type for IT0014 that would be used in a PCR after Function P0169 to cancel out the Wage Types created by that Savings Plan.
Upon enrollment, you would create the IT0014 with that WT (let's say X169, with number 1). During Payroll Processing, Function P0169 would generate the Deduction WTs but these would be cancelled out in a following PCR, resulting in no deduction for the current pay. Then, when you receive confirmation "that the bank has created an account for the employee", you delete the IT0014 with WT X169 and there is automatic retroactive calculations.
Note that, alternatively, the pcr processing WT X169 could also transfer the Deduction Amount into a non-remitted Deduction WT, and upon the confirmation of the Bank Account, the initial IT0014 with X169 would be delimited and an IT0015 with WT Z169 would be created so that in a pcr processing WT Z169, the cumulative sum of X169 would be used to generate WT X169 in negative and the regular Deduction WT in positive.