I want to know if it's different the acces by number to the SINGLE REGISTRATIONS between AUDYA 76 and AUDYA 4?.

I will explain my problem: I have an AUDYA 4 and I have created 999 SINGLE REGISTRATION (in one folder of course), in this folder I can create more SINGLE REGISTRATION (1000, 1001, 1002, etc.) but when I try to call the last SINGLE REGISTRATIONS, up to 999 I can't because only three digits can be used, (000 to 999). It's right or I'm wrong? In AUDYA 76 it's possible to make more than 999 SINGLE REGISTRATION.
Many thanks