Title: Retirement benefits and LWOP
Excerpt Quoted from OPM.GOV: "An aggregate nonpay status of 6 months in any calendar year is creditable service. Coverage continues at no cost to the employee while in a nonpay status. When employees are in a nonpay status for only a portion of a pay period, their retirement deductions are adjusted in proportion to their basic pay (5 U.S.C. 8332 and 8411).
High-3 average salary computations are based on periods of creditable service. Thus, periods of nonpay status of 6 months or less in a calendar year that fall within an employee’s average salary period are included in the calculation of the average salary using the rate of basic pay in effect during the period of nonpay status. For example, if a full-time employee whose annual rate of basic pay is $85,000 per year is placed in nonpay status for 3 months, that 3-month period would be credited in the average salary calculation using the $85,000 basic pay rate. (If the rate of basic pay changed to $86,500 per year after 2 months of the nonpay period, the first 2 months of the nonpay period would be credited in the average salary calculation using the $85,000 basic pay rate and the last month of the nonpay period would be credited in the average salary calculation using the $86,500 basic pay rate.)"
NOTE: This information is accurate as of the date of this post: 11-12-2018. Bolding added for emphasis.