I can share a couple of details to ensure you can manage your QuickBooks data, @VetBizGal2019.

For your first concern, each region has different conditions when deleting your QuickBooks Online (QBO) data. The article you provided is for Australia (AU) QuickBooks version. Thus, it states 90 days and only applies for the Plus, Essentials, and Simple Start users. You can toggle it to US to get the steps specific for your region.

For your second concern, yes, you're right. You'll lose your promo offers once you cancel your subscription (for both QBO and Payroll). For more insights, please review this article: What happens to my QuickBooks Online data after I cancel.

Since your data is worth 60 days, you cancel your subscription and then resubscribe to create a new company. Before doing so, I recommend printing or exporting your data to keep a copy for future use. 

When you're ready, here's how to cancel your account:

1. Click the Gear icon at the top, and then select Account and Settings.
2. Choose the Billing and subscription tab.
3. Pick Cancel subscription,and follow the on-screen prompts to continue.
   
   

Once done, please proceed to Step 2 under the If your books are 60 days old or older section in this article: Delete your data and start over in QuickBooks Online.

If you have multiple QuickBooks companies, you can use the same login info to save time. This way, you can switch between companies easily.

I'm always around to lend a hand if you have more questions about managing your QBO account. Take care and enjoy the rest of the day.