No, that’s not what I’m saying. That thread is long and discusses many issues relating to FTP results not being what was expected and what other users think about it. I was just pointing you to an existing body of knowledge so as not to reinvent the wheel.
What I think is, that if your Ramp Test and 20 min test were done in similar conditions (same equipment in the same location), then I would be looking in general at your power profile and whether you had particular strength in longer sustained efforts over more V02Max efforts that would explain the difference in test results. GCN did a good video on testing protocols that is worth watching:
However, as you state above, your tests were in very different conditions. One outside, the other inside which introduces a number of variables that can make a huge impact to your results. I agree with @madman2 that you should stick with the 234 number indoors and see how you go. If you find your workouts are way too easy, you could either increase the intensity of the workouts by say 5% and see how it goes, or redo your test.
What I wouldn’t do, is take your higher outdoor score and just use it indoors. More than likely it will turn your Sweet Spot workouts into threshold (or higher) and V02Max intervals into spontaneous combustion Neither of which are very helpful for your training.