...currently it goes like 100-110-121-133-146-161-177.... and so on. I like it be 100-125-150-175-200...
I partially disagree... The dynamic 10% zoom from step to step is much more smooth increasement than fixed 25% zooming levels.
Fixed zooming increasements are good for pixel art games when you want to see exact pixels, but for overall layout navigation and object-placements you want a smooth zooming transition.
And what about zooming out? 100 - 75 - 50 - 25 - 0? Hell no
Better to have a dynamic 10% zooming, but with an option to set manually a zoom level to be able to set specific zoom levels (33.333, 50, 200, 400, 800)