I have not noticed any difference, regardless of the weight of the bomb. I use the same technique to deliver all ordnance, and the impact point is always where I want it.
To me precision is a must with the Tiger now roaming about. A direct hit is required to kill that monster. A direct hit with a 500 lb bomb will disable it, but it takes a direct hit from a 1,000 pound bomb to assure a kill. So far, I have not seen any difference between the two in trajectory. Nor, for that matter, with the 2k and 1,800 kilo bombs either.
My regards,
Widewing