Running two businesses from home, not sure if one can include the garage while other doesn't

Hello. I've tried the Turbotax with live help however each expert is giving me different answers and I do not know which is true.
I am running two businesses from home as a sole proprietor. One is medical billing, which I started a few years ago, I have a dedicated home office for this one. The second one is an online store, I do not have a dedicated office space, however I use my garage as storage for my inventory.
Now, I was not including the garage in the total square footage of my home, since it is an unfinished space and is not calculated in the living area. However, I want to add the garage for my other business. That would result in two businesses showing a different home square footage.
If I include the garage in both businesses, my office area percentage will be lower resulting in higher taxes, it would also show different numbers than my previous year tax returns.

 

Is that fine to have first business showing smaller sq ft since it is not showing the garage, but the second business to include the garage?

 

I would really appreciate your help!