Serge, this is analogous to QCINs.
This brings up an old topic- here and there, notes within a brick are shuffled, and or removed, andthen replaced into a different position in a brick. They are essentially replacing themselves, so no true replacement function has taken place. QCIN is reffering to Quality control inspection notes. Sometimes this is the case, other times, there is no rhyme or reason.
Newer folk: For more info on "QCIN" search QCIN and read the threads that pop up. Interesting stuff.