In a past life I did some work on a project that used a data aggrigation service for investment accounts. I think something similar is used by many of these apps to retrieve transaction data. The accuracy of these apps in real-time cannot be any greater than what information is made available from the bank's transaction data.
The problem with real-time card transactions and pending status: many times the correct amount isn't available right away. This is common with pay-at-the-pump gas stations and places where you add a tip to the transaction. A 'preauthorization' is done at the time the card is swiped, but the transaction isn't finalized until the establishment does a 'batch settlement' of transactions - sometimes the end of the day, or maybe two or three days later.
This is made worse by the fact that many institutions don't even include pending transactions in the data they export or make available to the aggirgation service. For example, I can download transactions from my credit union. The pending transactions are not made available in this data.
It's one of the reasons I still do everything manually. Perhaps some day in the future, the banks and credit card processors will get together on a standard for transaction data access, and hopefully have some better way of handling these pending transactions.
