why OMMIC PHEMT have small and large signal modes

Dear all：
OMMIC's HEMTs have two mode ,one is large one is small signal ,why does the OMMIC design kit need to have two mode, other kits like tsmc don't like this.

3Q~

It's their choice.Some foundries like Triquint use a single molde for all conditions while some others use 2 different models for small and large signal operating modes.
Especially there are some divergency between foundries in term of modeling..