Removing weight often doesnt increase delta-v kerbal engineer redux

[MrClottom]

So i've been using kerbal engineer redux for a while and recently i've realized that in some rockets removing or changing the weight of a test payload doesnt effect the delta-v and sometimes even affects counter intuitively. So im trying to test a new 2 stage reusable rocket in career and in kerbal engineer redux increasing the size of the monoprop tank only decreases the deltav of the first but not second stage. and removing the tank removes about 300m/s from the second stage. NOTE: rcs is of in the kerbal enginner redux readouts. Could anybody tell me why this is happening and if it is a bug how i can fix this??

[MrClottom]

Oh i realize my error. it calculates the delta-v according to the root part and the root part was the second stage so it was calculating the delta-v as if i would be seperating my payload therefore not accounting for it's weight. why removing it completely increased the delta-v by a couple hundred m/s idk but that's trivial