I played OB in flight 50 the same day as Bernie. It was definitely longer than 5575, but bear in mind that Oyster Bay is a par 70 course. So, if it were the same total yardage as a par 72 course the Oyster Bay holes would play longer in relation to par than on the par 72 course. I think OB moves their white tees back regularly because there is a big gap between the white and blue tees (on the scorecard).
I don’t know which handicap service you guys use, but I was looking at my stat page on GHIN and saw that the PCC adjustment added a whopping 3 strokes to the regular white tee course rating that day. That adjustment can be added or subtracted depending on weather or other abnormal course conditions. Given that it was a warm and mostly calm day it wasn’t a Weather adjustment, so it had to be increased course difficulty, which was likely an increase in yardage. It wasn’t 6200 yards for us though. Flight 53 played a different day than us, so their setup could have been different, but you could check your handicap service to see whether the course rating that day was adjusted via PCC.