Air carrier captain reported hearing and reading back different distances for a crossing restriction...

Narrative:

I returned to the cockpit after using the lavatory and heard the first officer read back a clearance to cross fifteen north of mtata at FL290. The controller did not correct the first officer. We were shortly thereafter handed off to the next frequency and checked in at FL330. The controller asked us if we had a crossing restriction as the first officer did not supply it upon check in. The first officer said we were to cross fifteen north of matat at FL290. The controller said roger. When we reported leaving FL330 the controller asked about our clearance again. The first officer said we were to cross fifteen north of matat at FL290. The controller said the correct clearance was to cross 50 north of mtata at FL290. He then told us to cross mtata at FL250 which we did.better radio terminology would be to read back the clearance as fifteen/one five miles or fifty/five zero miles as this would eliminate any missed communication.

Original NASA ASRS Text

Title: Air carrier Captain reported hearing and reading back different distances for a crossing restriction. Fifteen miles was thought; but it was fifty miles. Also; the names of the intersections were extremely similar.

Narrative: I returned to the cockpit after using the lavatory and heard the first officer read back a clearance to cross fifteen north of MTATA at FL290. The controller did not correct the first officer. We were shortly thereafter handed off to the next frequency and checked in at FL330. The controller asked us if we had a crossing restriction as the first officer did not supply it upon check in. The first officer said we were to cross fifteen north of MATAT at FL290. The controller said roger. When we reported leaving FL330 the controller asked about our clearance again. The first officer said we were to cross fifteen north of MATAT at FL290. The controller said the correct clearance was to cross 50 north of MTATA at FL290. He then told us to cross MTATA at FL250 which we did.Better radio terminology would be to read back the clearance as fifteen/one five miles or fifty/five zero miles as this would eliminate any missed communication.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.

Attributes
ACN	1342384
Time
Date	201603
Local Time Of Day	1201-1800
Place
Locale Reference	ZJX.ARTCC
State Reference	FL
Environment
Light	Daylight
Aircraft 1
Make Model Name	Large Transport Low Wing 2 Turbojet Eng
Operating Under FAR Part	Part 121
Flight Phase	Descent
Flight Plan	IFR
Person 1
Function	Captain Pilot Flying
Qualification	Flight Crew Air Transport Pilot (ATP)
Events
Anomaly	ATC Issue All Types Deviation - Altitude Crossing Restriction Not Met Deviation - Procedural Clearance

Air carrier captain reported hearing and reading back different distances for a crossing restriction. Fifteen miles was thought; but it was fifty miles. Also; the names of the intersections were extremely similar.