Sounds good.
For me everything kinda has its time and place and runs its course and I just move on to the next thing.
If my results begin to plateau there are just way too many viable alternatives out there to just throw time, effort and money at something that just isn’t doing it for me.
As one guy I ride with puts it, “my legs are my coach” 
To the OP, 1.6% is an increase, so don’t feel disappointed.
As some have alluded to, what plan were you on, and what was your base?
What is your riding history? Lots of base, or a genuine new cyclist?
You may need to develop your aerobic base first, so that you have a big base to build your season on.
I.t.o. of my experience:
I joined TR in June and did the SS-MV plan and jumped 6.2%, but I felt more tired than when I was on other training plans I’ve done (coached and self-coached). I only did the plan to gain the experience of their plans, so that if friends ask, I have the experience.
I haven’t raced since February 2020 (a month before we had lockdown). Racing is only starting up again now, so I’ve been in maintenance mode for the last 18 months; just enjoying riding my bikes. Now that racing is returning, I’ve stepped up my training and I hope to get back to my 2016-2018 levels by Spring 2022 (southern hemisphere).
In prior years/seasons, the gains have been less each times (as the FTP increases). I’m expecting another 5-8% jump when I next test. The test thereafter might be 3-5%. With me being on a polarised approach, I’m keen to see how it pans out compared to the traditional methods used in the past.
I’m definitely new to cycling, began riding regularly may 2020, took all winter off, started again in April 2021, started TR July 2021.
I believe I am on the sweet spot plan. I am now seeing more anaerobic rides with VO2max being added but for the first to 6 week cycles it was:
Tuesday - Sweet Spot - 1hr
Thurs - Threshold - 1hr
Saturday Sweet Spot- 1:30min
I then squeeze lifting and endurance/recovery rides in when I can.
I don’t have access to the plans, as a non-subscriber, but doing anaerobic workouts on a low aerobic base isn’t advisable.
Read this article, which explains the aerobic base and why it’s important.
Sweet spot is not gray, but not bad either; it is aimed for those with time constraints, but I’ve seen a number of people say they are fatigued after doing blocks of SS training. The traditional base is for those with a little more time to train and is definitely easier to complete.