Need advice on stool columns

[arupd123]

Hello,

attached is a layout of my parental house

Number of existing floors = 2

My contractor has drawn up the plan for 2nd floor

a) Page 1 - section of ground floor [existing]
b) Page 2 - section of 1st floor [existing], which is exactly on top of the section of the ground floor shown in Page 1
c) Page 3 - planned section of 2nd floor[planned], which is exactly on top of the section of the 1st floor shown in Page 2

My question: The section of the 1st floor shown has 2 "stool columns", i.e. column rising from the terrace of ground floor. If I extend these stool columns for my second floor will that be risky? Since the room sizes on the floors are not similar, I am feeling a bit concerned on the stability of the structure.

Any advice would be appreciated.

Thanks,
Arup

Thanks,
Arup