No, I would suggest that you experiment and see whether this relation for you is more like 90 % or more like 95 %. Or if you use a ramp test, whether you should use 73 % of maximum aerobic power (which the ramp test measures) or perhaps the default 75 %.
Even small changes can make a big difference when it comes to workouts. Last time I tweaked my FTP it was by 2.4 %, and even there was some guesswork involved (I erred on the side of a lower FTP). To put into perspective how small that number is: my power meter has an accuracy of +/- 1.5 %.
Within the context of TR, think of FTP just as the power with respect to which you scale your workouts. So I would pick your favorite FTP test, be it ramp test or 20-minute test, and then validate that FTP with 2 or 3 workouts. In my experience threshold workouts and VO2max workouts work best. Your progression levels (if you use Adaptive Training) should put you in the 4–6 range initially in many cases. If it puts you in the 3s, I’d lower my FTP. If threshold, sweet spot and VO2max progression levels are all larger than 6, I’d add a few watts to your FTP. Make sure that workouts which AT judges as achievable should be achievable, i. e. they should not feel hard.