Couples without children have an easier time than big families when shopping for health insurance. Although a twosome pays the same premium as a big family in the same federal health plans, the couple has only his-and-her medical concerns.

That means lower out-of-pocket medical expenses. If you have health insurance but never see a doctor or dentist, insurance premiums are your primary health expenditure. But if you use your insurance, premiums are only part of your total medical outlay. Out-of-pocket costs can mount up.

Some fee-for-service plans require enrollees to pay a healthy (no pun intended) chunk of their medical or hospital bills. Even health maintenance organizations have added costs or co-payments that can increase the amount you pay every year--in addition to premiums.

Next year, a couple that is insured by the federal health benefits program and has "average" medical expenses can expect to pay a total of $1,870 to $7,960, depending on their health plan. Those figures--from the Washington Consumer's Checkbook guide to federal health plans--reflect premiums and likely out-of-pocket costs to a federal worker and the fed's legal spouse. The federal program doesn't cover domestic partners.

If a couple experiences major illness and medical costs, their total outlay in premiums and out-of-pocket expenses can range from about $4,000 (in the Blue Cross standard-option plan and the George Washington University HMO) to $10,000 (in the high-option Postmasters and Mail Handlers plans), according to Consumer's Checkbook.

Total outlays, in good and bad medical years, are going to be less if you use the preferred-provider option of your health plan. That means seeing a doctor or using a medical facility in the plan's network.

Here is the Consumer's Checkbook list of "best buys" for couples. (Monday's column listed "best buys" for singles.) The ratings are for nonpostal workers (postal employees have lower premiums and generally pay less in out-of-pocket expenses) and take into account premiums and likely out-of-pocket costs. The total projected cost to the consumer is expressed in biweekly premiums for next year.

* HMOs: Kaiser Permanente, $1,870; Aetna US Healthcare standard option, $1,910; George Washington, $2,010; Prudential, $2,230; M.D. IPA, $2,340; CapitalCare, $2,470; Aetna high option, $2,520; Free State, $3,280.

* Fee-for-service plans (preferred-provider option): Blue Cross standard option, $2,630; Mail Handlers standard option, $2,810; Association Benefit, $3,130; Postmasters standard, $3,380; Mail Handlers high option, $3,430; GEHA, $3,560; American Postal Workers Union, $3,590; Foreign Service, $3,620; National Association of Letter Carriers, $3,620; Alliance, $4,070; SAMBA (special agents), $4,310; Blue Cross high option, $4,330 and Postmasters high option, $7,600.

Couples also have the option of each signing up for separate coverage if they think that will be less expensive than buying family coverage.

Federal workers and retirees have until Dec. 13 to pick a health plan for next year. Most active-duty and retired feds are covered by one of the federal program's plans. To be eligible for lifetime coverage in retirement, feds must be enrolled in one of the federal plans for the five years before retirement.

Missing Pension Payments Some retired feds in Zip code areas 20017 (Brookland) and 20020 (Anacostia) found out the hard way this week that getting a pension payment by mail can be a problem. Civil service annuity checks for some--perhaps all--of the retirees in those parts of the District still haven't shown up. They will have to be reissued and a makeup payment mailed out. The checks should have been delivered Nov. 1.

The vast majority of federal retirees and survivors have direct deposit for their annuities. The money is transferred to their accounts electronically, automatically. None of them is waiting for payment.

Although most big employers require workers to sign up for direct deposit, the government still permits--though it discourages--retirees to get paper checks by mail. After this week's experience, some of the holdouts-- especially in the two unlucky Zip codes--may sign up for direct deposit.

Health Insurance Guidance At 9 a.m. tomorrow on WUST radio (1120 AM), Bill Smith, of the National Association of Retired Federal Employees, will talk about what federal workers and retirees should look for--and avoid--when picking a health plan for next year.

At 10 a.m. tomorrow on WUST, Tim Dirks, of the Department of Energy, will talk about trends and new issues in federal personnel programs and practices.

Health Insurance Seminars Rep. Constance A. Morella (R-Md.) is sponsoring two health insurance forums, both on Dec. 6, for federal workers and retirees. The first session, at 9:30 a.m., will be at the National 4-H Center, 7100 Connecticut Ave., Chevy Chase. The second session, at 7:30 p.m., will be at the Nuclear Regulatory Commission, 11545 Rockville Pike, Bethesda.

Parking is free at both sessions. Health insurance experts and representatives from different plans will be on hand to answer questions.

Mike Causey's e-mail address is causeym@washpost.com.

Friday, Nov. 12, 1999