The term "Erhöhte Notleistung" was used earlier for the 1,42 ata/2700 rpm rating while the original "Notleistung" rating was 1,35 ata/2450 rpm. That was the situation July 1942, see the last page of the document here:
http://www.wwiiaircraftperformance.o...t-30july42.pdf
Hermann probably has more information when the earlier rising of the "Noteistung" (from 1,35ata/2450rpm to 1,42ata/2700rpm) happened.