I get that, but… (with apologies for sort-of hijacking the thread)
…I think that time is a bit of a given? We know whether we’re looking at 60 or 90 or 120 minutes depending on what we’ve searched for, or what volume training plan we’re on.
And TSS is both flawed (30 minutes at 100% is the “same” as 60 minutes at 71% but I know which I’d rather do!) and hard to interpret instinctively.
Whereas when I look at IF, I can immediately get an impression of the difficulty. E.g “0.89 IF for 90 minutes, so that’s like riding sweetspot for 90 minutes, this will be hard”.