your GPA calculation will not be affected by the school. but considerations are given for schools known for tougher grading system because grade inflation is a serious problem at mid tier schools and some highly ranked ones.

for example, it's better for you to have a 3.5 at a tough/higher ranked school than a 4.0 at a crappy school.

also, your coursework matters. if you have taken graduate level and difficult courses, your chances go up.