OPM computation of formulas
Primary source
Verbatim text below is from the Electronic Code of Federal Regulations (eCFR), a public-domain U.S. government work. Always verify the current version with the eCFR before relying on it for any legal matter.
Full Text
(a) A court order directed at a refund of employee contributions is not a court order acceptable for processing unless the court order provides sufficient instructions and information so that OPM can compute the amount of the former spouse's share of the refund of employee contributions using only the express language of the court order, subparts A, D, and F of this part, and information from normal OPM files.
(b) To provide sufficient instructions and information that OPM can compute the amount of the former spouse's share of the refund of employee contributions as required by paragraph (a) of this section requires that the court order state the former spouse's share as—
(1) A fixed amount;
(2) A percentage or a fraction of the refund of employee contributions; or
(3) A formula that does not contain any variables whose values are not readily ascertainable from the face of the court order or normal OPM files.
(c) A court order directed at a refund of employee contributions is not a court order acceptable for processing if OPM would have to examine a State statute or court decision (on a different case) to understand, establish, or evaluate the formula for computing the former spouse's share of the refund of employee contributions.
This is legal information, not legal advice. Laws vary by jurisdiction and change frequently. Always verify current law with official sources and consult a licensed attorney in your jurisdiction for advice on your specific situation.