Help with scale

I’m trying to make a case for a headphone dac/amp and having trouble getting scale to be right. I make a rectangle the size of the unit with fillets and copy that and scale it 116% so I can cut the original box out of it so the unit fits inside but it doesn’t scale uniformly as the longer wider top is thinner than the shorter sides.

Here is a pic of what I mean the size of the interior is right but the outside is not uniform. What am I doing wrong? The print was done at high speed and .3mm layer just to check fit.

Thank you, lovely food

Can you elaborate further? Scale is uniform in all 3 axis (X,Y,Z). Did you select the entire body before scaling? I ask because of you selected portions of a body, then scale will work only those surfaces selected. I assume you did not do any scaling in your slicer before printing?

What did the part look like in Shapr? What Slicer are you using?

Print settings should not affect scale.

Are you scaling in the slicer program? Are in scaling in XY&Z at the same time?