Forehand Swinging motion: Practice vs Game Play

I've noticed in a lot of videos that there is contradictory advice from what players tell you to do vs what they actually do during games. 

1. Keep a consistent bat angle during swinging. A lot of coaches tell us to not 'turn' or close your paddle during your forehand forward swing. They say it's a bad habit of creating topsin and causes inconsistencies. However, I've seen J.O. Waldner and Xu Xin doing that a lot.

2. Swinging across the body. You always see/hear coaches tell you to NOT swing across your body. Instead, they tell you to stop in front of your body. I can definitely site videos showing pro players doing exactly that. They swing across their body. Of course this doesn't happen on every hit but you can see it happening a few times during the longer rallies or when they are smashing an open shot. example: Wang Liqin, a lot of the European players (Kreanga), even Ma Long sometimes.

Interestingly, the women's game seems to be more sound and more in line with what is coached. Is anyone else seeing these inconsistencies? Are these 2 tips really what developing players should be focused on?

>1. Keep a consistent bat angle during swinging. A lot of coaches tell us to not 'turn' or close your paddle during your forehand forward swing. They say it's a bad habit of creating topsin and causes inconsistencies. However, I've seen J.O. Waldner and Xu Xin doing that a lot.

They probably do this mostly against a slow incoming ball - and they have the timing to get away with it. Against a fast incoming ball, you normally don't want to be changing the racket angle as you forward swing. Against a slower ball, where you can generate a bit more whip by changing the angle as you forward swing - but the timing is more difficult. I often to this when going for an all-out rip against a backspin. 

>2. Swinging across the body. You always see/hear coaches tell you to NOT swing across your body. Instead, they tell you to stop in front of your body. I can definitely site videos showing pro players doing exactly that. They swing across their body. Of course this doesn't happen on every hit but you can see it happening a few times during the longer rallies or when they are smashing an open shot. example: Wang Liqin, a lot of the European players (Kreanga), even Ma Long sometimes.

They probably do this when rushed, i.e. they are barely getting to the ball, and so don't have time to change the momentum of their body, and so swing more with their arms. I do this sometimes as well. 

Hope this helps!