Its even got the wrong name! MATS Pt 1 still refers to TA being applicable "...in the vicinity of an airfield" or beneath CAS. So, at 18000' over the North Sea, which airfield are you in the vicinity of?
Your turboprop cruising at 17,000' approaches an FIR Boundary - there's something the other side at 18,000 and one at 16,000' on a different QNH; how does the conversation with Paris/Brussels ACC go?