Here is sg4 for refrence,
<SG4> A Robot may not Pin or Trap an opposing Robot for more than five seconds during the
Driver Controlled Period. A Pin or Trap is officially over once the Pinning Robot has moved away
and the Robots are separated by at least 2 feet (approximately one (1) foam tile). After ending a Pin
or Trap, a Robot may not Pin or Trap the same Robot again for a duration of 5 seconds; if a Team
does pin the same Robot again, the pinning count will resume from where it left off when the
pinning Robot initially backed off.
so that means that it isnt cumulative unless you re engage within 5 seconds or they haven't backed up at least 2 feet.