Lidia,

One thing you could try would be to adjust your "interim" baking parameters.
This means that, for the two bakes which will be followed by a spin step (i.e.,
bakes 1 and 2), perform a "soft" soft bake - reduce your bake temperature, and
your bake time.  You mainly just want to be able to freeze the material in
place.  Then, for the final process, perform a bake which is a little bit longer
than the single coat bake.

This will also allow better integration of the multiple layers.

Best Regards,
Chad Brubaker