Hey, happy to help.
The HBS calculator is for estimation only. However, in my case, it was quite close to the actual amount I got. They will literally require you to submit the similar documents to prove your financial situation and hence will calculate aid based on those. Therefore, if anything special or burdensome with your family (for example, I had to submit documents about my mother's health conditions and her expensive treatments in addition), you should also submit as one in the FinAid application.
In your case, if you got "not much" from the HBS calculator, it's an easy financial choice to go with GSB.
Also, curious how you got aid from GSB but not HBS. Is the GSB Aid other than need-based financial aid (for i.e, the Hennessy Knight, other fellowships...)?
Posted from my mobile device