Would increasing the relative thickness of the material be equivalent?

Plastic product design

Example 4.4 uses composite beam analysis by factoring the difference in material modulus of elasticity between the two materials times the width of the paint layer to “equalize” the materials in the composite.

Would increasing the relative thickness of the material be equivalent? (5 pts.)

There is a 12% error by not including the paint layer in the analysis, can you prove this? (45 pts.)

For reference see Example 4.3 and Session 6d for the analysis technique for composite beams.