Convert Excel model to iOS or Android app

Existing Excel model contains a large number of historical daily prices of an item. Given a date, an equation (supplied by me) used is to calculate a past or future price of the item for the app user and overlay the result on the historical price graph. ## Deliverables In addition to the high level summary, a forecasting equation (supplied by me) is used to calculate values to overlay on the actual historical prices. Upper and lower limits for the calculated values for any given date are also generated. See the attached sample graph. The app user enters a date for which a forecast price is then calculated. If the app user also enters the actual price for the same date, the app will indicate if the actual price is within the upper and lower limits for the corresponding forecast price. This may assist the app user with a buy/no buy decision for the item. The historical price database contains over 5500 daily prices. While this data may be viewed by the app user, it may not be changed by the user. However, the app developer (me) must be able to add to the actual price database and also change the parameters of the forecast equation before releasing an updated app to users. If the above described updating cannot be done without recompiling the app each time, I am happy to split the task into two exercises. ie a baseline app creation exercise and subsequent app update exercises (billed on a time basis). The update exercise is expected to be straightforward since it involves adding a limited number of fresh actual prices to the database. On occasion, modified parameters for the forecast equation may also be updated. A functional specification is available for qualified bidders replying to me.