Solid vs Joined Surfaces

 From:  Ronamodeler (RON_A)
6515.1 
Okay all you MoI geniuses...I need some advice, please.
Here is another formed plastic model I'm working on. It looks like a fairly clean (except for where I cut and stretched the bottom part) solid part. MoI and Rhino both tell me it isn't.
I constructed the outer surfaces from two sections, then joined them with a blend. Then I offset the resulting surface to a thickness of .040".
Can someone take a look and tell me what bad edges or other problems they see? I can use this for what I am doing, but I want to learn to make my models 100% correct.
Thanks!
Ron

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