I quickly noticed something was off here just by testing your formula in a different context. No results show which shouldn’t be happening.
This formula had a number of things wrong with it.
Contract Revenue in Progress =
CALCULATE( [Total Contract £ per day],
FILTER( VALUES( Contracts[Date On] ), Contracts[Date On] <= MAX( 'Event Dates'[Date])),
FILTER( VALUES( Contracts[Date Off] ), Contracts[Date Off] >= MIN( 'Event Dates'[Date] )))
So I updated it and now get a result.
Just a matter of following more closely the example here I think.
The formula had the date around the wrong way and also one of your operators was around the incorrect way also.
Thanks
Sam