Narrative:

I was the d-side responsible for coordination. I coordinated aircraft X at FL340 with ZNY. The aircraft had requested FL360 and was at that altitude already; but ZNY oceanic was unable FL360; therefore he was coordinated at FL340.I wrote down FL340 in red and circled it to show coordination as per SOP. The strip was offset and I did not flatten it.I was busy coordinating other aircraft and did not realize that my right side had terminated aircraft X to new york oceanic. The strip was laid flat on the bay; but he was not at FL340 and was still at FL360. I believe my right side must have not checked the altitude on the strip before he terminated; he was fairly busy.a few minutes after the aircraft progressed the fix; ZNY gives me a call and asks about the altitude of aircraft X. I see the beacon code north of the fix leton at FL360. I glanced down at the strip which was still in the bay; flat and noticed that FL340 had been coordinated.ZNY lost non radar separation (11 minutes crossing instead of 15) with another aircraft that was crossing through at FL360.I should have put in an interim altitude after coordination. This certainly would have helped. There are a couple of people in the area that do not like to use interim altitudes; but in the future I will be using them for coordination purposes at all times. Leaving the strip offset is something that can be easily overlooked when you are busy and having a visual clue on the screen certainly would have prevented this.this was a breakdown in teamwork. I should have personally gotten the attention of my right side to make sure he knew what altitude the aircraft was coordinated at; instead of relying on strip marking alone.

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Original NASA ASRS Text

Title: ZMA controllers reported passing incorrect altitude information to oceanic sector due to workload and misinterpreting flight progress strip marking.

Narrative: I was the D-side responsible for coordination. I coordinated Aircraft X at FL340 with ZNY. The aircraft had requested FL360 and was at that altitude already; but ZNY Oceanic was unable FL360; therefore he was coordinated at FL340.I wrote down FL340 in RED and circled it to show coordination as per SOP. The strip was offset and I did not flatten it.I was busy coordinating other aircraft and did not realize that my R side had terminated Aircraft X to New York Oceanic. The strip was laid flat on the bay; but he was not at FL340 and was still at FL360. I believe my R Side must have not checked the altitude on the strip before he terminated; he was fairly busy.A few minutes after the aircraft progressed the Fix; ZNY gives me a call and asks about the altitude of Aircraft X. I see the beacon code north of the fix LETON at FL360. I glanced down at the strip which was still in the bay; flat and noticed that FL340 had been coordinated.ZNY lost NON RADAR separation (11 minutes crossing instead of 15) with another aircraft that was crossing through at FL360.I should have put in an interim altitude after coordination. This certainly would have helped. There are a couple of people in the area that do not like to use interim altitudes; but in the future I will be using them for coordination purposes at all times. Leaving the strip offset is something that can be easily overlooked when you are busy and having a visual clue on the screen certainly would have prevented this.This was a breakdown in teamwork. I should have personally gotten the attention of my R side to make sure he knew what altitude the aircraft was coordinated at; instead of relying on strip marking alone.

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.