New sub company

Hi sign in issue,

You won't need to have another login (Intuit account credentials) to add 2 more QBO subscriptions.

All you need to do is select a QBO plan. Then, when you're on the signup page, you can click on Add another company and log in using your existing user ID and password. Here's an article for more information: Create or add another company file to QuickBooks Online.

Let me know if you have other questions in mind.

@sign in issue 

One QBO account is for one company file and you can use the same email address to open a new blank account for each company file. Otherwise, consider switching to QB Desktop with a time license to manage company files with a lower cost.

https://quickbooks.grsm.io/India