Hi Russell

Thanks for reaching out on Lucidchart Community!

While our shapes do often auto-size to match large increases or decreases in text size incremental changes like the one you are describing are not likely to be auto-sized. 

As a workaround you can select the group of shapes that you want to resize and then (while holding down Shift to lock the aspect ratio) resize a group of them at once.

Or if all 200 boxes are on the same doc you can go under Select > All Shapes which will select all the shapes on your doc and then you can (while holding shift to lock the aspect ratio) resize them all at once. 

If auto-sizing for incremental text size changes is a feature you would like to see implemented in the future please fill out our feature request form. Feature requests are passed on to our product team which may impact future roadmaps. 

Hope this helps!