I think the answer to this question is: "it depends". Compressing a bullet lower into the case can cause substantial pressure spikes but there are a lot of variables invoked such as how fast the powder burns, how deeply the bullet is seated, how tight the crimp is etc... In addition, some powders have allowable compression while others do not and the latter can cause massive pressure issues. Normally in the reloading world, we are only dealing with +\- 10% variabilities meaning that very small changes can make huge differences. A typical indicator is to examine the primer post-firing for symptoms of pressure spikes. Sometimes only a 1% change can make the difference between normal or over pressure.
I know I've taken the long road to get to your question, but it was simply to prove the point that there aren't easy answers sometimes. Long story short - without chrono graphing the load, it's very challenging to know where on the pressure/velocity curve you are and how close you might be to being dangerous or safe.