so have I but i want to learn how to do it corrtectly
is a 5% bombing accuracy from 20k plus good?
First, your bombing hit% is currently 439%. You probabky have the 5% form the ingame score sheet, which uses a different format.
Second, you hardly can use this number as a measure of your ability to hit something, and even less to compare yourself to others. Because the hit% depends mostly on
what you are hitting. Lazily dropping a big bomb on a cluster of buildings in the town will give you an insanely high hit % (because you "hit" many objects with that bomb), while taking out an ords bunker with pinpoint accuracy from 30k will give you actually a much lower hit % (only one object "hit")
So you can only judge your precision yourself. Do you reliably hit & destroy what you are aiming for? You do not have to make several approaches, or use significantly more ords than required by the object hardness? Then you are good at bombing.