Wide Area Telecommunications Service (WATS): under which calling pattern does a WATS plan tend to be less expensive than a flat-rate long-distance plan?

Introduction:
Wide Area Telecommunications Service (WATS) was a bulk long-distance offering that provided discounted rates within specified bands or calling zones. Organizations chose WATS when their traffic profile matched the plan's economics. This question asks you to identify the calling pattern under which a WATS arrangement typically saves money compared to a flat-rate approach.

Given Data / Assumptions:

• WATS pricing discounts apply across a high volume of calls in defined regions.
• Flat-rate (or standard tariff) pricing applies per call, often with per-minute billing plus setup.
• We compare total monthly spend under different usage profiles.

Concept / Approach:
The core idea behind WATS is amortizing fixed or banded costs over many calls. When call volume (the number of calls) is large, the per-call and per-minute charges of standard tariffs accumulate quickly. WATS becomes economical because the effective cost per call drops as usage increases. Shorter calls also help avoid hitting duration thresholds where per-minute accumulations overtake the WATS allowance; frequent short calls spread the fixed WATS cost efficiently. Conversely, occasional long calls may not justify WATS versus conventional per-minute billing.

Step-by-Step Solution:

Verification / Alternative check:
Historical procurement guidance recommended WATS for customer-service centers and sales operations making numerous short- to medium-length calls within certain distance bands, reinforcing the high-count, shorter-duration advantage profile.

Why Other Options Are Wrong:

• Always less expensive: false; savings depend on usage profile.
• Small number of long calls: standard tariffs often cheaper.
• Never less expensive: contradicted by high-volume use cases.
• None of the above: incorrect because one pattern is advantageous.

Common Pitfalls:
Treating WATS as universally superior; ignoring call-setup charges and band restrictions; forgetting that extremely long durations can exhaust WATS allowances and flip the economics.

Final Answer:
Less expensive only when the number of calls is large and each call is relatively short.