With the new re-jigging of the schedule now taken into account, there now remains a two weekly (Tues/Sat), A330-200 slot for a transatlantic route. I doubt they would use a two weekly slot to launch another destination. I think more or less they will use it for extra capacity on Europe in the evening after the A332 is back from FAO that morning (On Tues/Sat), either that or maintenance although I doubt the latter following the trends of schedules in the last few years.
2 gaps were kept during summer 14 and I think not certain it was 3 in summer 13 schedules also. You are right they did the odd rescue to Europe and replaced some delayed T/A departures. Majority of the time they were given a rest though!