I do this 4 to 4S ( or reverse ) connection quite often and 55 mins is plenty. Last month there was ground crew waiting for me as I disembarked (10 mins late) with a bright neon boarding pass which got me to the front of queues.

Other ground staff were very proactively aware of my tight connection and whisked me through in double quick time.

I made it with 20 mins to spare..
My cases made it too......