We do not want you to track every day after you've completed your TRINITY programme. It's a good way to achieve your goal because it allows for tweaking so you should always see results.
Maintaining your results is not easy! There is a tendency to slip back into old habits without a goal to aim for anymore but if you manage portion sizes and eat protein at every meal (and veg!), you can do it. Macros are based on your natural build so for example, if someone is naturally skinny, they might need to eat more carbs to maintain muscle. If you're doing these things and it's not working, tweak it a bit - eat a bit more or a bit less until you find the right balance.
It's also important to keep up the weight training, otherwise you will lose muscle and this results in slowing down your metabolism again.