I'm still not convinced - it doesn't matter how much you invoice...

I'm still not convinced - it doesn't matter how much you invoice because it is unearned, and will be earned over future months. I agree that the 0.6m is guaranteed revenue in the next quarters, but it doesn't guarantee that the next quarters will benefit from the same "unearned income amount". It works for this period, but I'm not convinced we can add it to further periods as a given?

I may be overthinking it... I'm an engineer not an accountant so have little experience with this..

If you are correct (and I hope you are!) then huge upside potential given that projecting the seasonally weak Q1 meets full year rev guidance.