There is no metaphysical or tiny zero involved per Theravada view. Theravada avoids apriori metaphysics like the plague; they follow the doctrine of momentariness, which may be like a tiny zero...lolol, maybe wrong, look up how long a mind moment lasts....citta...hahaha

Most of my focus in meditation has been just letting mind moments flow and not getting involved.

Recalling the past is still a mental object happening in the present. I love your questions @marcusantoniu; you are #agoodegg!

(PDF) In Theravāda Abhidhamma sati (smṛti) is a conditioning factor that occurs only in good consciousness and is called “right mindfulness” (sammā-sati). Sati appears frequently in the depictions of religious techniques connected with four applications of mindfulness: mindfulness of the body, mindfulness of the feelings, mindfulness of the mental events and mindfulness of the factors (dhamma).