Cash up records the cashflow into the business including any deposit payments . From an accounting perspective deposits are only recognised as revenue when the service is completed / product is sold. Cash up will reflect your daily payments through Slickpay or your reader into your bank. This should be used for daily reporting.
The Revenue report shows you exactly the value of transactions that have been recorded as checked out. This includes all services and retail products that have been billed.
The Revenue reports excludes deposits which have not yet been redeemed against a service but will include any services completed that had a deposit payment against them. This report should be used for filing taxes.