Originally Posted by
frankvb
[...] However in this case I'm guessing that the system simply is giving you the fully-flexible fare due to an internal problem. It was known to sometimes do that for slightly more complex routings. [...]
I spoke to someone on the BAEC help line yesterday and he was surprised to hear about my findings. We didn't go into too many details but he couldn't explain the difference of over €4000 and recommended booking over the phone. So some sort of error does sound logical.