BT Olympic Plan question..

I have been using the BT Olympic 20 week plan to prepare for my next race. I am getting ready to go into the 4th week. The first 3 weeks have been great workouts and fairly intense, but the 4th week is more of a rest week and not as strenuous based on the reduction of s/b/r times.

The swim times  for example, have gone anywhere from 29-48 minutes the first three weeks, and next week it is calling for a 17 minute swim on Monday. My question is this:

Do I go all out on the 17 minutes, do I take it easy for this week recover or do I push it to still get in a workout? Thoughts?