Importing data into an existing Airtable table with formulas can be tricky. The key is to ensure that the structure of the data being imported matches the existing fields. If your data includes formula-based columns, you'll want to double-check that formulas are correctly configured post-import to ensure they work as expected. Using CSV files or third-party tools might streamline the process.

Could you provide screenshots of both tables with the relevant fields, specifically the linked field between the tables? 

If you could provide a read-only invite link to a duplicated copy of your base with no records in it I could take a look at this for you! https://support.airtable.com/docs/adding-a-base-collaborator#adding-a-base-collaborator-in-airtable

Just to understand your question, because there is a difference in excel vs airtable in the way the relation between tables work. Also importing can sometimes cause a few hiccups. 

1. Can you double check that the fields you are trying to use formulas on are numbers/currency not single line text?
2. How are you referencing with the formulas the values that are in "Income Account Transactions"? Have you created a linked field and then looked up (or rolled up) the values you require in the table called "Profit & Loss"? Because you can't reference fields from other tables if they are not linked and looked up first.