Hi Ben,
Yes - to insert a cue between two other cues, simply set up your scene and tap 'Record'. Then type the cue number between the two cues you want to insert your new cue between. Then hit the 'GO' button, or alternatively if you have an external keyboard connected you can press 'Enter' to submit your action.
As @kgallen said, cue numbers have the ability to be identified with up to a 2 decimal place number, so I could have 0.99 or 0.58 if I wanted.
For example:
If I wanted to insert a cue between 1 and 0.8, and I wanted its number to be 0.9, I'd tap 'Record', type 0.9 and hit 'GO'.
I recommended to connect an external keyboard to your console as it can help in numerous scenarios with the keyboard shortcuts that are available for use.
You can access the on-screen touchpad via hitting the Z key on your FLX S24 console.