Overall Laminate Strain in Femap

What do you mean "overall strain"? Do you mean of all laminate elements?

I was always under the assumption that on an element basis, every ply should have the same strain.

every ply should have the same strain only if there are only in-plane loads and the layup is symmetric. If there are bending loads, or unsymmetry, then the strain is linear thru the thickness.

if each ply has a different loading then it'll have a different strain. For example ...

1) unidirectional plies under axial load, all plies have the same load/stress/strain
2) a laminate of 0,+45,-45 plies ... under any load each ply will have different load/stress/strain as permitted by the elasticity of the adhesive.

"Wir hoffen, dass dieses Mal alles gut gehen wird!"
General Paulus, Nov 1942, outside Stalingrad after the launch of Operation Uranus.

Yes thank you to SWComposites and rb1957 for the clarification. In that case to answer the OP, you would have to envelope the laminate strain results on all the plies in the model.