My original lab was Quest 3+3, Bostwick 3+4, MSK where treatment was done wanted to do their own read. Agreed with Bostwick 3+4 with minor difference as to percentage.
As I recall, on a second opinion Epstein downgrades about 8%, and upgrades 20%. Interestingly, in 1.4% of the cases, he finds no cancer at all.
In my case, he downgraded from G7 to G6.