Hi Janusz.
There is a tendency, in A&P and in Equanimity Regarding Formation (High Equanimity) to wonder off, and that's okay. Also there is a tendency during the peak periods of A&P and E.R.F. (Equ.) to adapt and explore your experience (the four objects of mindfulness), which is sort of natural. The important thing is to be aware of your attachment to pleasant, without avoiding enjoying it in an effort to remove the attachment to pleasant. Also to be aware of your attachment to not wanting pleasant states to pass.
The thing with A&P during your peaks, you'll either fall back into the 3 characteristics or forward into the dark night depending on your centre of gravity. This is because, either you wandered to much in your practice and the line between exploring new things and getting distracted was crossed, for to long a period/to many times. Or because of entropy, meaning its hard to keep it up all day long.
But with Equanimity, you only fall back, and this can be, well devastating at points, (he he.) maybe because you only have a week to go... and then three days and you still haven't attained equanimity for a few hours every day, let alone stream entry.
So, yes its fine to not always be totally, just with the rising and falling of the breath, and to explore the changing formations through out the rest of the body! But if the practice isn't developing or if it's getting to hard, then you can or should come back to rising and falling.
In equanimity sometimes the breath becomes very subtle and the mind isn't sharp enough to actually see the breath clearly, there is no need to push it to hard at this point. If you want to increase your clarity, stay 'relaxed', keep your 'stability' of the object, and 'clarity' will come! Increasing attention to gain clarity, can turn to tension very easily.... You will be able to see the breath more clearly despite it being very subtle, with relaxation, stability and clarity in that order.
*("A/P cycle" - noting abrupt passings until noting accelerates past the ability to consciously track individual sensory incidents. Noting becomes an operation of intuitive tracking below consciousness. The speed of tracking peeks at whatever the vibrational frequency of the object of meditation is. Followed far enough, this results in coming out of all that clarity and speed into 'normal' reality with a deep awareness of the vibratory nature of the structure of my surroundings. Because concentration is so high and so much more is readily available to conscious awareness, it feels that another cycle is harder to realize.)
Sounds like your really working it! Is that to get back to it again, if so recognise that, is it because you want to get to equanimity, if so recognise that? The above description sounds very A&P, and a lot of fun, makes we feel a bit wistful. Yep everythings vibrating, (and changing really fast!) and that's kinda cool

.
Maybe, keep an eye on the quality of mindfulness and calm in the mind. Look for the subtle aversion and craving and also for the vedana, if you want to progress? Or just enjoy it while your at it! If you keep pushing to hard, to get there, with the-get to it approach and the investigation, you will start to push your self past these peak A&P experiences, which are quite fun. If you keep the mindfulness and calm of momentary concentration going, rather than trying to get to it, again and again (if that's what your doing?). Then the transition into dark night might be a lot easier, is my guess. Shrug. Also that approach, just works better for equanimity, too.
Take Care. from Neem