Good for you to get this lactate test. And also its a good observation on your part that your aerobic base is somewhat deficient right now. With a 30 beat spread you do have some basic work that to do that will pay big dividends over time. If you have the time to do more aerobic work then by all means do it now. It will pay off big time next winter which is still 5-6 months away. Extend the plan by repeating these early weeks of the plan while building volume. You can never have to much aerobic base.