Your in the honeymoon stage Stu. Up until recently your body was not used to doing any of these movements at all let alone getting better and stonger at them. For a while you will be able to see the increase growing like it is but you will get to a point when it will slow up. This will be the same for your body improvements too.

Enjoy it while you can.

As long as you are still controlling the movements and are capable of doing them it is perfectly safe. You are obviously doing something right as you are getting stronger.