I agree with you he said his back was to the bed. If the change in his reenactment is to be believed, the light from the balcony, which we know was on and still on when the police arrived, would have shone into the bedroom. How could he not have seen the bed and therefore Reeva? It seems OP shoots himself in the foot with his every move!
This aspect of the trial exercises me somewhat! So I did an experiment with a fan in our bedroom (I think Judgejudi did the same or was it someone else). The fan was not as large - about 14" inches but it was of the standard type (ie with a pedestal). Carrying the fan, I could not hear my OH close a bedroom door hard some 20ft away. The window in OP's alibi is about 30ft or more away, ie past the cupboards, along the corridor to the bathroom and a further 10 ft on from there. I have just had to do it again because I was sure he said his back was to the bed but the reenactment shows him to be behind the fan. Quite frankly I couldn't hear the bedroom door being hard closed on either occasion. The noise of the fan completely obliterated any other sounds. I know my fan was not the same but his was much larger and I think his would have created more wind sound.
Why on earth didn't forensics carry out this exercise? I am sure it would have proved the window could not have been heard above the noise of the fan and that would have determined OP's innocence or guilt (IMO) at the outset.
Like many here, I think the reenactment could not be used because it did not tie in with OP's evidence. In fact I think it may have incriminated him.