Jody said it best:

“Dual insurance is SO much more complicated than people think.”

And she’s right.

Patients think dual coverage means:

“I’m covered twice.”

Dental teams know it really means:

“Buckle up.”

Because there isn’t just one type of Coordination of Benefits (COB).

There are multiple.

And the difference between them is the difference between:

A smooth claim

A patient balance

A zero-payment surprise

Or a refund you didn’t expect to write

Let’s break this down the way your team actually needs to understand it.

The 4 Real Versions of COB (And Why They Matter)

Terminology varies by carrier, but structurally, most dental plans follow one of these models.

If your team doesn’t know which one they’re dealing with during verification?

You’re guessing.

And guessing is expensive.

1️⃣ Traditional COB
(Full Coordination / Standard COB)

This is what most providers think dual coverage means.

How it works:

Primary pays according to its fee schedule.

Secondary looks at the remaining balance.

Secondary may pay:

• Up to its allowable, or

• Up to what it would have paid as primary.

Sometimes both plans pay off their own allowables.

And yes, occasionally, total payment exceeds your billed fee.

Sounds great, right?

Until you realize:

If you’re in-network, you typically must refund any overpayment.
If you’re out-of-network, it can get murky, but ethically and legally, you cannot retain payment beyond the charge for the service.

Reality check:

Many offices quietly leave that overpayment as a patient credit.

Let’s just say… that’s not a best practice.

2️⃣ Maintenance of Benefits (MOB)

Now we start tightening the screws.

Under MOB:

Both plans apply their own deductibles.
Both plans apply their own copays.
Both plans apply their own frequency limitations.

Secondary does NOT simply “pick up the rest.”

Patients often still owe.

MOB preserves each carrier’s cost-sharing structure. It is not designed to eliminate patient responsibility.

Translation:

Dual coverage does not mean zero balance.

And if your financial coordinator promises that it does?

You’re creating tomorrow’s uncomfortable phone call.

3️⃣ Carve-Out

Carve-Out gets confused with non-duplication, but they’re slightly different.

Here’s how it works:

Primary pays normally.

Secondary calculates what it would have paid as primary.

Then it subtracts what primary already paid.

It only pays the difference (if any).

Example:

Secondary allowable: $1,000
Primary paid: $800
Secondary pays: $200

But if:

Secondary allowable: $900
Primary paid: $1,000

Secondary pays: $0.

Carve-Out prevents duplication but still allows some “fill-in” when secondary has a higher allowable.

It’s not terrible.

But it’s not magical either.

4️⃣ Non-Duplication (Non-Dup)

This is the one that causes the most heartbreak.

Under Non-Dup:

Secondary looks at what primary paid.

If primary paid equal to or more than what secondary would have paid, secondary pays $0.

If secondary allowable is higher, it may pay the difference.

But most of the time?

It pays nothing.

And here’s the kicker:

Same-carrier exclusions often apply.

If both employers offer plans through the same carrier, say a company like Cigna, and the employer-selected plan includes a non-dup clause:

The secondary will not duplicate payment.

Even though premiums are being paid on both plans.

Why?

Cheaper premiums.

Employees don’t see that when they enroll.

They just see “dual coverage.”

The “No Secondary Benefit If Primary Exists” Clause

Some plans go even further.

If there is valid primary coverage:

The secondary provides no benefit at all.

That’s beyond non-dup.

That’s essentially a “no COB” provision.

In that scenario:

The secondary policy cannot be used if another plan is primary.

Patients often don’t realize this when enrolling.

But contractually?

That’s the benefit structure their employer chose.

Why This Matters So Much for Your Practice

From a revenue standpoint:

Traditional COB = Potential windfall (watch for refunds).
MOB = Patient balance almost guaranteed.
Carve-Out = Limited secondary value.
Non-Dup = Usually zero benefit.
No-COB clause = Secondary policy functionally unusable.

Now imagine your team doesn’t verify which structure applies.

You estimate optimistically.

Patient pays less.

Secondary pays zero.

Now you’re collecting after the fact.

Or worse…

You write it off to “keep the peace.”

That’s not a billing problem.

That’s a systems problem.

The Refund Issue Nobody Talks About

When carriers overpay beyond your billed charge:

You cannot retain that overage.

Whether refunding to the carrier or patient depends on:

• Network contract

• Assignment of benefits

• State regulations

But keeping money beyond your charge?

Not defensible.

Even if “the patient never paid a dime.”

The Hard Truth About Dual Coverage

Dual insurance is not automatically better.

Sometimes it:

Increases administrative work
Increases patient confusion
Increases AR
Increases refund risk
Increases write-offs

And sometimes?

It provides little to no additional benefit at all.

The Leadership Question

Is your team trained to:

Identify the COB structure during verification?
Explain realistic expectations to patients?
Estimate conservatively?
Avoid revenue leakage?
Manage overpayments correctly?

Or are they still operating under:

“Two insurances means they’re covered.”

Because that sentence has cost this industry millions.

Quick Recap

Dual insurance isn’t one thing, it’s five possible structures.

Traditional COB can overpay.
MOB preserves cost-sharing.
Carve-Out fills gaps selectively.
Non-Dup often pays nothing.
No-COB clauses make secondary unusable.

If your team doesn’t know the difference, you’re not coordinating benefits.

You’re gambling.

And in dentistry, margin matters.

The practices that win don’t complain about insurance complexity.

They train for it.

Is your team ready?

Benjamin Tuinei
Founder – Veritas Dental Resources, LLC

Jody Lujan
Client Success Architect

📞 888-808-4513
Services: PPO Fee Negotiators, PPO Fee Negotiating, Insurance Fee Negotiating, Insurance Credentialing, Insurance Verifications
Websites: www.VeritasDentalResources.com, www.VerusDental.com