I understand now, thanks for elaborating. To clarify, the Phone and AltPhone fields are stock QuickBooks fields which is why they cannot be deleted. Why don't you just create two custom fields in QuickBooks when editing one of your customer records, name them Phone 2 and Phone 3. Make sure to put a checkmark in the 'Cust' column so they are added to the Customer table, and select Any text under the 'What kind of data?' column.
When you perform a Full Sync those fields will come over to Method where you'll be able to utilize them on screens and have the data sync between QuickBooks and Method. Edit your screen, drag the new fields on the screen, then position them where you like, and change the Caption names of the three Phone fields to make them display as needed, i.e. Phone (h), Phone (o), Phone (c).
You don't need to build a table for each screen, you can build more screens based off the customer table, or alternatively use the Retrieve Value from Table action and use the action result to populate into the appropriate fields on the screen.
In regard to the error being displayed, it has something to do with your Set Active Record ID for Screen action. It would be very helpful to have a screenshot of the message. If you can't upload it to a image upload/sharing site then email it to me.
- Ashur