BTW…I posted my rules for tough intervals.
"1.) Never end a workout during a recovery period. Always start the next interval. If you need to get off the bike and walk around a little bit, great, but always get back on and start the next interval.
2.) Never start an interval at less than 100% of workout intensity.
3.) Always try to make it half way through the interval at 100% intensity.
4.) Never reduce intensity by more than a few percent. Give it at least 30 seconds. A minute is better."
But, if you have to follow those rules for a workout like Kaweah your FTP is too high. Kaweah is 10 minute intervals at or a little less than FTP. If you can’t repeatably do 10 minute intervals at a given power, that power is not your FTP. This was my very first TR lesson. 
Kaweah was the teacher!