Actually there is not a simple inverse relationship between muzzle velocity and pellet weight. So if the pellet weight is increased by x%, the velocity does not go down by x%.
The pellet velocity is actually proportional to 1 over the square root of the pellet weight.
In my example, a 5.74 grain pellet gave 200 fps. If I were to increase the pellet weight to 7 grains this should theoretically give a muzzle velocity of 181 fps, all other things being equal.
In case you think I am a mathematical genius, I just plugged the numbers into one of the many available online calculators:
https://www.airgundepot.com/airgun-c...s-article.html