I think there is a lot of variation from school to school.
My youngest is still in college on financial aid and her school won’t budge no matter what. She worked at a dry cleaners for two years to help out 
The resources of the school, how much they want you, the impact of your personal financial story, and whether the school considers it fair to address merit via financial aid would all be factors I would think.
After years of very detailed paperwork on finances for financial aid offices, with precision to the cent, I am surprised that schools will move the financial aid award figures around (like Columbia). We had to justify what we needed to the nth degree (my husband had had a stroke).
But then again, Columbia does not give merit aid, I believe, so it would have to come through financial aid I suppose, if they wanted to convince a person to come. Or do they have hidden merit? I have never heard this about Ivies but I didn’t have occasion to. The conventional wisdom is that Ivies have a waiting list of folks who can pay, so they tend not to increase aid without a good reason. But clearly albertsax got an offer so………
Frost, on the other hand, does apparently have merit so they can stick to financial aid based on figures given, formulas and special circumstances- math- since they can use merit aid to sway (help) admittees.
This is potentially complicated when dealing with different school and even different degrees. And we don’t know the financial status involved for the OP (no need to divulge!). Again, I think the simplest way is to deal straightforwardly with either financial aid or merit or both through the appropriate contacts. At Frost that would be through the contact for merit unless you have special circumstances.
As always there seem to be a lot of parents dealing with appeals on various threads and they seem pretty expert on it, including many dealing with Frost. akapiratequeen among them.
ps I will continue to view moving the financial aid offer up a hidden merit, In any case. It is an incentive to attend. Formulas are made to be bent I suppose.