That letter & response should be copied to the Minister of Transport and the MP for both constituencies, the pilot's & CAA's, should be asking questions in the house. Is the CAA not still answerable to the government?
I had this wishy washy experience with the old 100hrs in 28 days. The ANO said quite clearly that the limit was exactly that. However, my roster had me taking off at 95 hours on a 10hour sector and westbound. CAA confirmed I could takeoff even though I landed on day 28 at 105hours. HOW? They would not answer. I then asked them what would happen if I went east and landed on day 29 locally, but day 28 at home base? The silence was deafening. They didn't have an answer because they didn't have a clue about the question.
Regarding the first scenario; I was planned to land in USA at 105/28. Day off, then repeat and land back in Europe at 102/28, the 2 days off and then down south with 3 days off to reduce the rolling 28hrs by enough to seat all over again.
The CAA were clueless how to interpret the law. Astonishing.