Do I owe more money if I had a qualifying retirement coverage error and the employee retirement deductions for the new retirement plan are more than what I already paid?

If I was in CSRS during my qualifying retirement coverage error, paid into the Fund more than I would have paid as a CSRS Offset, Social Security-Only, or FERS employee, and end up retroactively in one of those retirement plans, will I get a refund of the excess I had withheld from my pay?

If I am like the person in the previous question, but the amount I paid as deductions under CSRS is more than the amount of combined retirement deductions and Social Security taxes due for my new retirement coverage, will I get a refund of the excess?

If my qualifying retirement coverage error occurred while I was a reemployed annuitant, and I am later corrected retroactively to a different retirement plan, will I have to pay any additional amount for retirement deductions?