If you prefer the more cardio over strength workouts - I'd suggest 15% isn't bad because you have your workout days with no deficit. So your 4 days at 15% and 3 days at no deficit actually average out to 9% deficit overall weekly.

So eating 1400-1600 and then on exercise days added calories.

So I'm trying to get a handle if your overall deficit for the many months was minor or major.

If workouts are about the same, then your TDEE was higher then with higher weight, so above 2400 easily.

15% deficit to that would be 2040.

So likely never reached that - certainly not on rest days, unlikely you ate more than 800-1000 on workout days.

So you had a rather extreme deficit this entire time.

If you are really going to try to do this different eating levels on different days depending on workouts or not - you'd be better served not attempting to use a system that relies on average weekly totals and deficits and eating amounts.

You'd be better with MFP method, which assumes a non-workout day, and eating more on workout days.

Just set to maintenance, pick the correct activity level for your non-exercise part of day (lightly active if you have kids or dog or busy after even a sit-down desk job).
Then see what your maintenance calories would be looking at food diary.

Now take off 15% - and go adjust your daily eating goal manually - mess with macros to hit your desired diet type.
Say this ends up being a 300 cal deficit, only on non-workout days.

Now on days you exercise, log the workouts so your daily goal goes up. (where are you getting calorie estimates from?)
If you truly want no deficit on these days - you know you can eat 300 cal more and be fine.
If you keep the deficit you set, at least you'll know it's still 300, even though your literal TDEE this day went up, so deficit is smaller than 15% now.

Yes, this is going to sound confusing - but it sounds like you have some methods you want to use that don't fit to the average weekly TDEE method of same calories daily.

I like my Fitbit charge HR, I do manually add in my strength training.
It made me realise just how much more active I was than I thought.
It confirmed I needed to increase calories.
They are good as a guide to hit.
Ichel
EM2WL ambassador and moderator

A scale is a huge help to get an idea of what a serving is. I'm always weighing my peanut butter, because it is so dense. I've had min for years because I like to bake with a scale when I can and I use it to stretch the cereal out for the kids and to weigh my food when I need to.