Yes, you can “skip” the ramp test at the beginning of the plan since you just took one and the results are in line with where you think they should be. Similarly, as you work your way through SSB, if the workouts become too easy, you can insert a ramp test as needed - just be smart about your rest and recovery going into it as well as the potential impacts on follow on workouts.
In general the TR plans use periodization and progressions. Periodization being 3 or 6 or 8 weeks on followed by a recovery week. Progression being similar workouts getting harder week after week (i.e. more time in zone, higher intensity, etc). You have as much flexibility as you want to move workouts around, but be conscious to maintain the progression and periodization as best as possible. The plans are not so rigid that you have to do every workout, exactly as it shows up in the plan, on the exact day it is scheduled - just be wary of deviating too far from the recommendation.