Would it be better to do an extra interval if you had the legs for it? One of the most challenging questions to answer is when is the right time to stop doing intervals. More intervals will usually inspire your body to grow stronger. So, if you can maintain the correct intensity for an extra interval, you will probably get even stronger.
But I have to underline the importance of not burning out. If you cannot complete that extra interval, you will have to pay for it. There are both psychological and physiological debts you have to pay afterwards. Therefore, I always recommend you steer well clear of failure training.
That means you have to stop intervals BEFORE you cannot maintain the correct power output.
On Day 7, you are the one to decide when you have had enough. I would like you to stop the intervals at the point where you are entirely sure that you could do one more interval if you had to. It is not an easy job because you are supposed to push yourself very hard, but not too hard. However, this skill characterizes many successful cyclists and has developed over many years.
Total time: app. 1hr
10min incremental warm-up
5min 70% VO2 max
3min 75% VO2 max
2min 80% VO2 max
10min 60% VO2 max
?? x (30+30sec) 100 / 50% VO2 max (close to your max repetitions, but no failure training)
15min easy rolling