Bevan, weight and balance - page 6 of CAAP 233 - the software/data/algorithm must be validated.
Functionality Level 2
6.10 In addition to the Functionality Level 1 capabilities, the EFB has one or more applications that utilise algorithms within a software application that require manual input to satisfy operational requirements. These include, but are not limited to, the weight and balance and/or performance calculations as required by the aircraft’s approved flight manual for use by the aircrew. The software applications must be validated to ensure the outputs from the application comply with the limitations detailed in the aircraft’s approve flight manual, for example any weight control shall be validated by an authorised weight control officer in accordance with Civil Aviation Order 100.7.
Being a wrong headed, stupid indvidual who is all thumbs, I will do my workings on Ozrunways but I always cross check with paper and pencil and that provides a written record to satisfy any FOI who asks.