Can you adjust a Mission Script based on player difficulty?

I see that you can SET the difficulty in a mission script, but can you *read* it? It would be nice to be able to do something like this:

Each time ship_spawn_timer finishes:
Create one new enemy ship at the wormhole arrival point.

if difficulty is <= 3 and ship_spawn_timer finished:
reset ship_spawn_timer to 300 seconds.

if difficulty is in the range [4,7] and ship_spawn_timer finished:
reset ship_spawn_timer to 200 seconds.

if difficulty is >=8 and ship_spawn_timer finished:
reset ship_spawn_timer to 150 seconds.