Great! Here you have tha API reference guide, and also the function which gets the account information:
it displays an important?message: "Important:?only?two?active summary subscriptions are allowed at a time!" So if you press the button more times maybe you will get unexpected behaviour or no data sent from TWS.?
Here's the screenshot of what I just downloaded today. I realized the problem goes away if I don't change to an xlsx file and leave it in xls - then its like all the lines are populated at once instead of waiting for a few seconds each line like this.