Hi Steve,
If your AMPLIFi 75 firmware is v2.0 (v2.1 is now available, BTW) and you have the latest version of the AMPLIFi Remote App, you should have 100 Presets. Sometimes, after conducting the firmware update, the other 24 banks show up as <EMPTY>. I've fixed this by conducting a simple factory reset again and it restores all 100 presets.
Turn your AMPLIFi 75 OFF Pushed down on the TONE button and MASTER Volume Knob simultaneously while turning the unit ON. Hold it until the white LED is on the first tone again. Pair the amp and check for the presets.