Hi Jay,
Congratulations on the 17lbs lost! Great work!

That 3lb might be about something else, eg if you had some inflammation in your body, you hold more water to help with healing, if you have been eating extra salt. Sometimes scales respond to humidity or other changes. So keep your eye on the trend over weeks and months rather than the daily up and downs.

This longterm view becomes more and more important as you get closer to your healthy weight.

But many of us have had to look again at our ‘normal days’ once we get our fast days working.
Some people find they need to set their TDEE https://thefastdiet.co.uk/how-many-calories-on-a-non-fast-day/ for the weight they aim to be, rather than the weight they are.
Some people find they need to cut out junk food altogether, or particular foods that seem to hold them back from losing weight (bread and pasta seem the most common).
Dr Mosley advocates the Mediterranean Diet as the basic lifestyle on non fast days.

My experience of being 5 years on these forums is that some people do, some people don’t, but the most productive thing seems to be to concentrate on the good fast days, and make gradual changes to your non fast days to make them healthier.

5:2 took me to the lower end of my healthy weight range, but I do need to keep a check on my NFD eating as an extra snack or a bit of comfort eating does lead me to put on weight.

Hope you have a lovely loss next time on the scales!