There seems to be some confusion in interpreting the Airbus communication about thrust lever position and exactly how it relates to reverse/autobrake/spoiler behavior in a possible overrun situation. A careful read of posts 424, 426, and some pages of the "GE 536 Occurrence Investigation Report" (link below) from Taipei is informative. The A320 at Taipei landed with #2 reverse disabled, and #2 thrust lever was left at 22.5 degrees after touchdown. Being somewhat above the throttle lever angle defined as "idle", spoiler extension was prevented even though reverse was used on #1. See the ground spoiler extension logic diagrams provided in both the factual and final reports. Autobraking was also suppressed, and diagnosis/response took approx 15 sec before manual braking began. For the busier who don't have the time to read all of it, see Section 2.3 Flight Operations, and Section 2.4 Stopping Distance (pages 83-93) of the final investigation report. This contains a good summary as well as a stopping distance analysis. Note especially in Table 2.4-1 that the combination of delayed braking, no spoilers, and somewhat higher EPR on #2 added up to a required rolling distance of 7800 feet for a 55,000 kg landing weight (although there appears to be some tailwind component). This was more than 4000 feet beyond what would have been required if #2 throttle lever had been closed and autobraking and ground spoilers deployed as planned. The calculations predict the Taipei A/C was at 67 kts at overrun on an 8550 ft (2600 m) runway with touchdown at 1750 ft (533 m), leaving 6800 ft (2072 m) usable.
As has been said before, any relevance to TAM 3054 will have to wait for the final analysis, but Airbus' release of the throttle lever guidance suggests it's important for A3xx pilots to clearly understand the implications.
GE 536 Occurrence Investigation Report
http://www.asc.gov.tw/acd_files/189-c1contupload.pdf