Well, considering the fact that the A123 battery pack is not one of the types recommended by Futaba, we'd really not know what could have caused the glitching. Futaba recommends using 4-cell or 5-cell packs of NiCd or NiMH chemistry. They have no recommendations for other types of battery pack chemistry.

For most models, failsafe events or glitching is caused by voltage difficulties in the system. Something could be causing the system to have large voltage drops. Momentary loss of control could be caused by a variety of things. The only thing that's common is the airplane. The twitch happening at full throttle indicates a possible vibration difficulty. Vibration can affect nearly everything in the airplane, from the servos, to the battery, to the receiver, to any switch(es), connectors, and so forth. Isolating such a difficulty, especially after a crash, is not particularly easy.

We can check your equipment, but cannot predict costs if repairs are needed. We really cannot guess what the actual difficulty may be.