I have problems to reproduce the elastic engineering constants in HyperSizer for single ply laminates with angles other than 0° and 90°.

I created a generic ply material and created effective laminates with (100% 0°, 0% 45°, 0% 90°); (0% 0°, 0% 45°, 100% 90°); (0% 0°, 100% 45°, 0% 90°). In the attached Excel spreadsheet I calculated the ABD-Matrix and from these values the elastic engineering constants according to

http://hypersizer.com/help/#Materials/EffLam/el-properties-stiffness.php.

I checked the calculation with 2 composite analysis tools: eLamX² and alfalam. The calculations in my spreadsheet and the two composite analysis programs are identical.

However, for the (0% 0°, 100% 45°, 0% 90°) effective laminate, the engineering constants are different in HyperSizer than in all other calculations. They don't even match the values from the equations from the link.

What am I missing?

A second question: Why do effective laminates, defined as symmetric and balanced, create coupling stiffness terms in the B-matrix?