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?

CFR · 2024-01-01 · US · Title 5

Yes, either OPM or your employer, as appropriate, will issue the payment in accordance with OPM instructions.

official document · source cfr-2024 · id 5:§ 839.803