PAM 111 Power Reserve Question

[Kevin of Larchmont]

I’m new to Panerai by less than a week. I know that Panerai states this watch has a 56 hour power reserve. I’ve been tracking my power reserve in the short time I’ve owned this watch and once I’ve gotten 36 hours and once 34.5 hours; I have many mechanical watches so I know this watch is fully wound. Curiously this watch is deadly accurate losing only about two seconds a day. I bought the watch from my preferred Rolex AD who took it on trade without box or papers or spare strap or strap tool or any evidence of prior service; it is a series J, 2007. It came to me with a two year warranty so they will be servicing it but my question is what mechanically could be causing a lower power reserve in a watch that still runs accurately?