Quick rundown:
Did Sustained Power Build HV and tested w/ 305FTP at completion (+6%).
Did SSBHV2 and tested w/ 305FTP at completion.
Starting Sustained Power Build HV again…should I modify any of the workouts, esp. the threshold (95-99%), to longer duration intervals?
I know I’m carrying far more muscular endurance into the plan than when I did it the first time around, and even with the increase in power, the shortish intervals (once again) might not force enough adaptation.
Thoughts? 
I wouldn’t do the same build twice. Pick a different one. Your body requires novel stimulus.
The same kind of things happen to me quite often. I found that a quick checkup of non-cycling related stuff in my life is generally more beneficial than changing anything in my training.
I go through my cycling block (4-6 weeks data) and ask :
a) did I sleep enough ?
b) did I eat enough and decently ?
c) did my family, life or job stressed me too much ?
Generally if one of those things go bad, I don’t improve much no matter what I do on the bike. So, I try to take care of that first.
Might not be the case for you, just a general thought.
Hmmm…again, it’s the path which was recommended by the TR crew. 
A Race is a TT.
What better plan than SPB?
I don’t care if DNF everything else this season…but I want to win that one.
They recommended you go Base Build Base Build and repeat the same build twice?
Or is there a typo and you meant to say SSB1?
Perhaps try the 20 minute test rather than the Ramp test for your FTP. It seems it might deliver more relevant data for your TT goals, and the test itself is good training for those goals.
Correct.
I’ll see if I can dig up the posts — both Reddit & TR forum.
Think a Gen Build —> 40TT Spec would be a better option at this point?
That’s what I’d lean towards. Whenever I see a plateau in people across any type of sport, it usually means they have been doing too much of the same thing.
Yeah some VO2 work could help make some room for future FTP gains
What @stevemz said. And what have they said in the podcast about raising your VO2 ceiling to make gains in ftp? Your cup may already be full, and by varying the stimulus (ie. Gen Build) then you can get a bigger cup that you can then fill again.
General Build HV goes something like this:
pt. 1: Threshold 2x; Sweet Spot 1x; VO2 1x
pt. 2: Threshold 1x; Sweet Spot 1x; VO2 2x
Sustained Power Build HV is:
Threshold 2x; Sweet Spot 1x; VO2 1x
So…not really different.
My mod plan for SPBHV was something like:
Threshold 4x; VO2 1x
But now considering going back to my own formulated plan from last pre-season:
Threshold 3x + VO2 2x.
It did for me what the TR plans have done, but in half the time. 
The last I recall you heavily modified TR plan such that it wasn’t a TR plan anymore. So I’m a bit lost.
I would do, in your case: 2 vo2max WO really fresh and a FTP WO. The rest endurance ( to be fresh for VO2 work)
Not totally true.
First time through Sus Power Build I did 5 workouts/week instead of 4, thus shortening the plan from 8 weeks to 6; zero workout substitutions. I think I added 2-3 extra workouts.
During SSBHV2 I did pretty much the same amount of work laid out in the TR plan, just at longer durations.
During my first time through SPB, I upped my FTP to 300 during the 3rd week, so basically I did most of the plan with the same FTP I currently have. What I’m questioning is if doing the same plan with the same FTP going to result in lesser improvements than doing the plan with some modifications.
At this point I’m satisfied with my duration capabilities, I’m now looking to improve my power.
You eliminated both rest weeks in SSBLV 1 and 2.
You said SPBHV was compressed from 8 weeks to 5, by eliminating a rest week and moving workouts. Your TSS chart shows 6 work weeks.
As of the first week of January those were no longer TR plans. They weren’t even periodized plans as far as I can tell. They appear to be make “TSS go up and to the right at all cost” plans. I’ve never seen any plan eliminate recovery weeks that are crucial to adaption. Maybe you changed things in Jan/Feb? I’m confused.
My read would be that you’re not giving your body space to adapt and recover.
Do an unmodified base plan, maybe turn down the intensity too, then go back into build.
Yup. Doing ~4hrs a week didn’t require I take a week off. Plenty of rest built into the plan.
Yup. I did a pre-plan week coming off being sick and a rest week, but 5 weeks of work.
Last pre-season, as stated above, I did 3x Threshold and 2x VO2/wk for 12 weeks (w/ 3 failed workouts). I know what my body can handle but that’s not the question.
The question is: will doing the same plan with the same FTP produce any increase in power or will modifications be required to induce adaptations?
I believe mods will be necessary. Having finished 3 months of nothing but Threshold and Sweet Spot work, I’m a bit stimulus stagnant. Perhaps I’ll give the VO2Booster plan a go before moving on.
I removed my post as it didn’t add to the OPs question
You already know this, there isn’t a single correct answer. Personally I’ve seen different power gains with same FTP and same plan.
Folks have already commented you would likely benefit from different stimulus for this block. If it was me, most likely would do general or short build and toss in a 2 hour ride (1 hour threshold + 1 hour tempo) on the weekend. Going off my best season, I’d actually do two of those a week on 2/1 week blocks.
Back on the periodization topic, even though your last post strongly signaled you want to shut down that thread of conversation:
This isn’t semantics, look at your latest TSS chart:
That is 6 weeks of work starting the last week of November.
Here is a typical periodized schedule for a 4 week block:
And your current plan going forward has 7 weeks without a real adaptation week:
My biggest gains in FTP actually came from super overload - averaging something like 500-600 TSS work weeks and tossing in a 800-900 work week (century) - coupled with periodizing cycles of 2 weeks on / 1 week adaptation (low TSS or not riding at all). Why 2/1? Didn’t feel like I needed 2/1 because my body could handle it, the 2/1 happened because I travel for work. And then later I looked at data and realized I had fallen into a 2/1, and the extra adaptation weeks appear to have pushed my FTP higher. My 2 cents FWIW.
I listened to an interesting podcast on Sunday driving home from a race, if you haven’t heard it, worth a listen:
https://fascatcoaching.com/chronic-training-load-ctl-for-masters-cyclists/
Thanks for the link. I am excited to listen to this podcast episode 