Bus Creator position by script

Hello,

I need to add inputs to a bus creator by scripts. Thats not a problem, but aline the bus creator then properly is not that easy, as the upper and lower end is also changing, so just adding the distance of the input blocks to the bus creator position does not work. I couldn't find out a reasonable pattern how it is changing, also for different distances of the input it seams that the ends are differently changing ... is there a pattern or an method to have a nice bus creator alignement ?