After the first 400 hurdle races in a season are ran, it's time to make use of the carvahlo-race-analysis in training. Once the weaknesses in a race are identified you have to choose at wich point little adjustments can have a large impact. It is very common problem's occur in one of three Carvahlo's main parts of the race. In that case redoing the early season Carvahlo training is a good option. If you are experiencing problem's with the change over at hurdle 5 (or 8) it makes sense to do the same kind of training but, instead of running hurdles 1 to 4 (4-7), your run hurdle 2 to 5 (5-8) and adjust recovery accordingly.
It is not uncommon you are having two problems at once. One of the most occuring combined problem is a changeover problem at hurdle 6 thru 8 with a lack of endurance. Running Carvahlo's for this part of the race could be unwise for you would be trying to solve two problems at once. Your lack of technique will make it hard to make it a good endurance training, where your lack of endurance will not allow you to work on your stride-pattern for a long as you would have to. Because your lack of endurance will not be easy to compensate, you should work on your stride pattern.
By increasing the distance between the hurdles gradually as much as one or two feet per hurdle, the athlete will experience an artificial fatigue. Now you can work on change over's, switching from stride length to frequency, running the same stretch over and over again, without having real fatigue playing a part.