Do damage rig effects stack with non-rig damage modules without penalty?

Question

The description for Hybrid Rig Collision Accelerator I, a rig slot damage increaser, warns that:

Penalty: Using more than one type of this module or similar modules that affect the same attribute on the ship will be penalized.

A Magnetic Field Stabilizer I, a low-slot damage increaser, carries the same warning.

Does that mean that a ship equiped with both would suffer the stacking penality?

Or does the penalty only focus on the same slot type?

Answer 1

I tested this out with the above items and there did not appear to be any stacking penalty between the rig slot and the low slot items.

Thus stacking penalties may be restricted by slot.

Answer 2

They count against each other for stacking penalties.