I think the 14 minute gap between the engines last sending data & there being no transponder response is a bit of a red herring tbh. The engine data is only transmitted every 30 minutes, as far as I understand it, so it transmitted at 1:07 & wouldn't have been due to transmit again until 1:37.
This isn't directly related to MH370 but am taking the opportunity to pick Goldie's brains/musing re aeroplane black boxes.
If all kinds of data can be sent from planes, why can't the data from black boxes be sent or accessed remotely? I suppose that if every plane in the world sent that data would be cumbersome when the majority reach their intended destination safely? But then that data wouldn't have to be analysed & could just be wiped when a plane landed. In this case, if black box recordings were available, the search area could be narrowed down somewhat.