No that’s not what I mean - you are misunderstanding. The advice I am giving you is specifically for your situation where you do not have enough systems to fill the page. I mean in the case of a page that is not full, the default justification settings cause it to spread out the systems too much because it is trying to put the bottom system at the bottom of the page with the top system at the top and it is trying to equally spread out the remaining systems in between that. If you change the settings, instead the systems will get bunched up close together at the top of the page (with a big gap below the bottom system) instead of with big gaps in between each system. This sounds like what you want. This is a setting change I regularly make in Dorico too, as if a page is only a little over half full I don’t want huge vertical gaps between staves and would instead rather have them closer together at the top of the page for readability by the performer.
This post is for Dorico but explains the behaviour (albeit unfortunately only with an example of a score and not parts):
What you probably want is the top example with high percentage values. You don’t necessarily have to use 100%, even 90% or so will probably be fine. The default I think is 60% which means if the system is a little over half full it will add spacing to stretch everything out to fit the page - this is not what I like and I always change it to 90% or so (or maybe even more) for readability by performers.
Again, I emphasize - these settings make almost no difference when the page is completely full, or nearly completely full. It is only when the page is not completely full that these settings really have an impact. You are trying to say these settings will not help you because your page is not completely full, and meanwhile these settings are for exactly your situation - where there are not enough systems to fill the page. Try it and you will see.