Interviewer agreed to schedule another interview but...

(I know I need to improve my English so please bear with me) I recently applied for a quant strategist role in HongKong and had 3 one-on-one video/phone interviews with EDs on that team. They always have so many questions for me and I'm probably a bit too talkative. These sessions are supposed to be 30 minutes long but for the first and third ones we talked for more than 45 minutes which I hope is not a bad sign. 

What makes me confused is that towards the end of my second interview, the interviewer asked me a typical "why move to this position from your current role?" question. This is actually something I'm waiting for because based on my research and networking I do have some clear detailed and innovative ideas related to their business. I said, "I wished we have more time because I do have my own vision about the future of XYZ and want to share it with you". He sounded interested and said "How about I grab A (the first interviewer) and we have another video call... let me check my schedule...". Then we closed the call soon afterwards as we ran out of time.

However, I was notified by HR to have an interview with the 3rd interviewer (which went fine) and an additional round with an MD (in the coming week). I also sent a regular thank-you note the day after (didn't mention the "original plan" as I don't want him to feel pushed). Didn't get any response so far. Maybe he is too busy? Should I expect the MD round to be final? Maybe it is stupid to even propose that idea? I'm not that confident to get the job but wonder if I can draw any lessons from this experience. 

Thanks a lot! Really appreciate your time and help.