Why does checking inline parameters optimize out blocks?

R2013b.

When I selecte Inline Parameters I find that some simulink blocks get optimised out of the generated code.

All I want is for constant parameters to be #defined, so why this side affect?

Some of the blocks that are optimised out are very similar to some others that are not so I really don't undersand the rules that are being following by the Simulink model build.

The block reduction setting has no effect for this case.